Chemistry Experiments

What may be the reason for geometrical isomerism?

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Restricted rotation about a double bond.

Isomerism exhibited by tartaric acid

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Optical isomerism

Isomerism exhibited by maleic & fumaric acid

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Geometrical isomerism

Most volatile hydrogen halides

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We all are familiar with the different types of hydrogen halides. Do you know which are they? Remember that the different types of hydrogen halides include HF, HBr,HCl & HI. Do you know among these halides which is the most volatile?
Note that the most volatile hydrogen halide is HCl.

What is ammonal?

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Remember that ammonal is a mixture of aluminium powder & ammonium nitrate.

Do you know the reason why sodium nitrate is not used in gun powder?

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This is becuase it is hygroscopic.

What happens when sodium burns in excess of air?.

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Sodium peroxide is formed.

Solubility of AgCl precipitate

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I hope chemistry students are familiar with this fact. this is an experiment commonly done in labs. Remember that AgCl precipitate is soluble in ammonium hydroxide solution.

Which is the type of bond seen in HBr molecule?

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Polar covalent bond.

Do you know the number of different oxides formed by nitrogen?

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I hope chemistry students are familiar with this question. You should know the correct answer as this is an important point.
Remember that the number of different oxides formed by nitrogen is five.

Do you know the reason why there is low solubility of AgCl in water?

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The low solubility of AgCl in water is mainly due to its high lattice energy.

Solubility of lower alcohols

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This post is related to the solubility of lower alcohols.
My question is:
Do you know the reason why lower alcohols are readily soluble in water? The answer is that the readily solubility of lower alcohols in water is mainly due to the fact that they form hydrogen bond in water.

The meso form of tartaric acid is neither laevo nor dextro rotatory. why?

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This is an important question related to tartaric acid. Do you know the answer? If not, check the below points.
Answer:
Meso form of tartaric acid is neither laevo nor dextro rotatory mainly due to internal compensation.

Among the following which is known as vitamin B12?

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Options:

Cyanocobalamin
Retinol
Riboflavin
Pyridoxine

Answer: Cyanocobalamin

Cyanocobalamin:

As stated above cyanocobalamin is known as vitamin B₁₂. Actually cyanocobalamin is needed for the normal production of red blood cells. It is also required for the nerve cells. Remember that the deficiency of cyanocobalamin results in a disease known as pernicious anaemia. It is important to note that vitamin B & C are water soluble vitamins.

Retinol:

Retinol is known as vitamin A. This is a fat soluble vitamin. Do you know the deficiency disease of vitamin A? Remember that the deficency of vitamin A results in a disease known as xerophthalmia & night blindness.

Riboflavin:

Vitamin B₂ is known as riboflavin. It is interesting to note that this vitamin is seen in green vegetables, milk & liver. The deficiency of riboflavin results in inflammation of the tongue.

Pyridoxine:

Remember that the another name for pyridoxine is vitamin B₆. This vitamin is seen in cereal grains & milk. It is important to note that the deficiency of pyridoxine results in retarded growth & dermatitis.

Clemmensen reduction of benzaldehyde yields.......

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Answer: Toluene

Do you know what is meant by clemmensen reduction? It is important to note that clemmensen reduction involves the reduction of aldehydes & ketones to hydrocarbons by using amalgamated Zn & concentrated HCl. This is represented by the following equation:
CH₃COCH₃---->CH₃CH₂CH₃

Among the following glassess, which type is used for making superior type laboratory apparatus?

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Options:

Pyrex glass
Hard glass
Soda lime glass
Flint glass

Answer: Pyrex glass

Pyrex glass:

It is interesting to note the properties & composition of pyrex glass. The most important property of pyrex glass is that it has low coefficient of expansion. Do you know anything about the composition of pyrex glass. The composition of pyrex glass includes

Silica 80%
Al₂O₃ 3%
B₂O₃ 12%
CaO 0.5%

Hard glass:

Hard glass is also known as potash glass. Remember that hard glass has a higher melting point. Also note that if we use K₂CO₃ instead of Na₂CO₃ in the manufacturing process the product obtained is known as hard glass.

Flint glass:

Flint glass is used in making prisms because of its high refractive index.

Orthosilicates & Disilicates

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Orthosilicates & disilicates are the different types of silicates. Before going into the details we should know how to represent the simplest silicate anion. Remember that the simplest silicate anion is represented as SiO₄^4-.
Orthosilicates:
It is important to note that silicates that contain the simplest silicate anion are known as orthosilicates. There are different examples for orthosilicates.
Examples for orthosilicates:
Zircon Zr[SiO₄]
Phenacite Be₂[SiO₄]
Disilicates:
Disilicates are also known in another name. Do you know which is it? Remember that disilicates are also known as pyrosilicates. Also note that disilicates contain Si₂O₇^6- units. An example for disilicate is Sc₂(Si₂O₇)

Borazine can act as a reducing agent.why?

2010-11-25T07:05:00.000-08:00

Borazine can act as a reducing agent because it is moisture sensitive & can be hydrolysed to hydrogen & boric acid which is represented by the equation.
B₃N₃H₆ +9H₂O---> 3H₂ + 3H₃BO₃ + 3NH₃
_{.
Also see Borazine.}

Borazine

2010-11-25T06:51:00.000-08:00

First remember that borazine is also known in another names. Do you know which are they? Remember that borazine is also known as Borazole & Inorganic benzene. Borazine is represented by the formula B₃N₃H₆. Borazine is considered as an example for heteroatomic polymer as well as a cyclic polymer of aminoborane.
Why borazine is known as inorganic benzene?
This is an important question which chemistry students should be able to answer. We all know about physical properties & chemical properties. Remember that borazine has similar physical properties with benzene. Also note that they are aromatic as well as isoelectronic. So it is important to note that borazine is also known as inorganic benzene.
why borazine acts as a reducing agent?

Boranes

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As the name indicates, boranes are hydrides of boron. They are colourless compounds with a special property that it is diamagnetic. It is important to note that there are 3 classess of boranes. Do you know which are they?
Classess of boranes:

Nido-boranes
Arachno-boranes
Conjuncto-boranes

The above mentioned borane classess are represented by a general formula.

General formula of borane classess:

Nido-boranes: B_nH_n+4
Arachno-boranes :B_nH_n+6
Conjuncto-boranes: B_nH_m

Benzoin condensation

2010-11-25T03:39:00.000-08:00

Chemistry students should always be familiar with the reactions & reagents involved in it. My question is benzaldehyde undergoes benzoin condensation in the presence of .........

Answer:
Potassium cyanide

Reaction of glycerol & bismuth nitrate

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Do you know what is the product formed when glycerol undergoes oxidation with bismuth nitrate? Remember that the product formed is mes oxalic acid.

Hardening of cement

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Do you know the process involved in the hardening of cement? It is interesting to note that this is mainly due to hydrolysis & hydration.

Important question

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Why CuSO₄ is not stored in aluminium bottles?

Answer:

This is because Cu gets reduced.

What is the shape of XeF4 molecule?

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Square planar

What is the product formed when phenol reacts with phthalic anhydride in presence of concentrated sulphuric acid?

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Phenolphthalein

Example of non reducing sugar

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Cane sugar

Example of lyophilic solution

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Starch dispersed in hot water

Interesting question

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Experiments are part of a science student. This is an interesting question. Among the 2 options given below, can you name the flame which has maximum temperature?

Bunsen burner
Oxy-acetylene

Answer is Oxy-acetylene.

Polytetrafluoroethylene is known as

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Teflon

Name the product formed when phenol is heated with KOH & chloroform

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Salicylaldehyde

What is Lucas reagent?

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Lucas reagent is HCl & ZnCl₂

Which is the common variety of coal?

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Coke

What is freon?

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Freon is CF₂Cl₂

Do you know why handling of acetylene is dangerous?

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This is because acetylene is an explosive.

Another name for chlorobenzene

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Phenyl chloride

Alkenes & Alkynes

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Alkenes are represented as C_nH_2n & Alkynes as C_nH_2n-2.

Main source of alkanes

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Petroleum is considered as the main source of alkanes.

Paraffins

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The term paraffin means little affinity. The other name for paraffins are alkanes. Do you know the reason why alkanes are known as paraffins? This is because alkanes are relatively inert to some common chemical reagents like acids, alkalis etc. It is important to note that alkanes are represented as C_nH_{2n+ 2}.
Remember that alkanes are defined as aliphatic saturated hydrocarbons with no functional groups.

Hydrocarbons

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What are hydrocarbons? Organic compounds with carbon & hydrogen atoms joined by covalent bonds is known as hydrocarbons.

Borax

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Borax is represented by the formula Na₂B₄O₇.10H₂O

Water sterilisation

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What do you mean by water sterilisation? There may be some harmful bacteria present in the water. So the removal of this harmful bacteria by means of destructive oxidation is known as water sterilisation.
It is very important to note that in a small scale this process is done by boiling the water. Also we know that liquid chlorine is used to sterilise water. Remember that liquid chlorine is a powerful oxidant.

Neutral oxides

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Do you know what are neutral oxides? Some oxides do not react with acids or bases to form salt. Such oxides are known as neutral oxides. That means neutral oxides are neither acidic nor basic oxides.
Examples of neutral oxides are H₂O, CO.

Uses of sulphuric acid

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It is important to note that sulphuric acid is also known as oil of vitriol & king of chemicals.
Uses

Drying agent
Dehydrating agent
Sulphonating agent

It is also used in the manufacture of

Paints
Synthetic fibres
Plastics
Fertiliser
Detergents

Interesting questions

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Following are some of the important questions. Every chemistry students should be familiar with this.

What is slaked lime?

Answer:

Slaked lime is calcium hydroxide which is represented as Ca(OH)₂.

What is lime water?

Answer:

Lime water is the saturated solution of slaked lime in water.

What is milk of lime?

Answer:

It is important to note that milk of lime is a suspension of slaked lime in water.

Biogas

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Biogas or gobar gas is a mixture of methane & carbon dioxide . Do you know how this is prepared? By the anaerobic decomposition of cow dung, biogas is produced.

Another name for gobar gas

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Biogas

Siemens gas

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Siemens gas is also known as producer gas. I hope everyone are familiar with the term producer gas. It is interesting to note that there is also another name for producer gas.Do you know ? It is also known as air gas.
Remember that this is a mixture of CO & N₂.
Uses of Siemens gas

Fuel
Reducer

Uses of blue gas

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Fuel
Reducer
Manufacture of methanol

Water gas

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What is water gas? Water gas is a mixture of CO & hydrogen. This is also known as blue gas. By passing steam through incandescent coke at 1000 degree Celsius, water gas is obtained. This is represented by the equation C+ H₂O----> CO + H₂.

Nucleophiles

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The important feature about nucleophiles is that they are also known as nucleophilic reagents. They are neutral or negatively charged species which are Lewis bases. That means they are capable of donating an electron pair.
It is very important to note that nucleophiles attack the region of low electron density in the reacting molecules.

Problem related to molality

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A solution contains 53 gram of anhydrous sodium carbonate dissolved in 250gram of water. How can we calculate the molality of the solution?

Solution.

Here use the equation molality=w/MW

w=53

M=106

W=250 gram=0.25 kg

Therefore molality=53/106*0.25=2

Molecular weight of a substance

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What do you mean by molecular weight of a substance? The molecular weight of a substance means it is the sum of the atomic weight of the elements present in one molecule of the substance.

Expression for molality

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It is important to note that molality is expressed in moles/kg

Molality & Molal solution

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Molality is the number of moles of the solute dissolved in 1000gram(1 kg) of the solvent. In general we can say that
Molality =Number of moles of the solute/Weight of the solvent in kg
Also note that if w is the number of grams of the solute with molecular weight M & dissolved in W kg of the solvent, then
Molality =w/MW

One molal solution
One molal solution means solution which contains one mole of the solute dissolved in 1kg of the solvent.

Molarity & Molar solution

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Molarity is a chemical unit used to express the concentration or strength of a solution. What do you mean by molarity?
Definition for molarity
Molarity is the number of moles of solute present in one litre of the solution. In general we can say that
Molarity of the solution=Number of moles of the solute/Volume of the solution in litres
Also we can say that if w is the weight in grams of solute dissolved in V litres of the solution & if M is the gram molecular weight of the solute, then we can say that
Molarity= w/MV
Definition for one molar solution
One molar solution means it contains one mole of the solute dissolved in one litre of the solution.

Solution,Solvent & Solute

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Do you know what are solutions, solvents & solutes? A homogeneous mixture of two or more substances is known as solutions . It is important to note that solute is the substance present in minor quantities & solvent is the substance present in larger proportions.

Normality & Normal solution

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Every chemistry students should be familiar with these terms. Actually what is normality? First remember that normality is a chemical unit used to express the concentration of a solution. Do you know the definition for normality?
Definition for normality
Normality is the number of gram equivalent of the solute present in one litre of the solution. In general we can say that
Normality of the solution=Number of gram equivalent of solute/Litres of solution.
Also it is important to note that if w is the weight in gram of the solute & E is the equivalent weight of the solute present in V litres of the solution, then
Normality of the solution =w/EV
We can prove this by the following problems:
Problem 1:

How can we calculate the number of grams of solute in 300ml of 1.5N NaOH solution?

Solution:

Given normality=1.5 N

Volume of the solution= 300ml= 0.3 litre=V

Equivalent weight of NaOH =40=E

So here the equation used is Normality of the solution= w/EV

Therefore w=1.5*40*o.3=18 gram

Problem 2:

How can we calculate the normality of a solution containing 224gram KOH in 2 litre of the solution?

Solution:

Normality=Number of gram equivalent of the solute/Volume of the solution in litre

Here volume = 2 litre

Number of gram equivalent of the solute=224/56=4

Therefore normality=4/2=2N

Definition for one normal solution

One normal solution means it contains one gram equivalent weight of the solute per litre of the solution.

Mole fraction of a solute

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What is mole fraction of a solute? This is the ratio of number of moles of the solute to the total number of moles present in the solution. In general we can say that
Mole fraction of the solute= Number of moles of the solute/Total number of moles present in the solution
For example : Do you know how to calculate the mole fraction of CH₃OH in a solution which contains 64gram of CH₃OH in 144 gram of H₂O?

CH₃OH is methanol. So mole fraction of methanol is calculated using the above equation. That means number of moles of solute= 64/32=2
Total number of moles present in the solution=( 64/32) + (144/18) = 2+8=10
Mole fraction of methanol=2/10=0.2

Fehling's solution

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What do you mean by fehling's solution? This is an alkaline solution of a complex copper tartrate & is prepared by adding a solution of CuSO₄ to an alkaline solution of Rochelle salt. Do you know what is rochelle salt? Rochelle salt is sodium potassium tartrate. Remember that this solution is violet in colour . On warming with aldehyde this is reduced to a red precipitate of Cu₂O.

Fenton's reagent

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Chemistry students should be familiar with some important reagents. This post is about fenton's reagent. It is important to note that fenton's reagent is a mixture of ferrous sulphate & hydrogen peroxide. For the oxidation of ethylene glycol to glycol aldehyde, fenton's reagent is used.

An alloy of iron & carbon containing 0.1 to 1.5% carbon is

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Steel

How lead is isolated from the sulphide ore?

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By air reduction method

Calamine contains

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Zinc

Name the concentration method used for sulphide ores

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Froth floatation

Duralumin is an alloy of

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Al, Mg, Cu, Mn

Stainless steel contains

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Fe, Cr, Ni

White lead

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2PbCO₃.Pb(OH)₂

Give an example of a substance which absorbs carbondioxide from air & gives oxygen

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Ozone

Name the process used to prepare Fe

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Aluminothermic process

18 carat gold contains

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75% gold

Plaster of paris is prepared from

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Gypsum salt

The dual nature of electrons was put forward by

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Louis de broglie

What is the name given to the space within an atom where there is maximum probability of finding an electron ?

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Orbital

What is the shape of the p orbital?

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Dumb bell

In german 'Aufbau' means

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Build up

What is the number of degenerate orbitals in d sublevel?

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Name the orbital with the greatest number of possible orientation?

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Shape of the orbital is determined by which quantum number?

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Azimuthal

Important Note

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Orbitals with the same energy are said to be ..........

Answer is degenerate.

What is the electronic configuration of chromium?

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1s²2s²2p⁶3s²3p⁶3d⁵4s¹

Give the number of umpaired electrons in a Helium atom

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No unpaired electrons

Sublimation

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Sublimation is an important process for the purification of organic compounds. That means from non volatile substances, volatile organic compounds are separated by this process.

What do you mean by sublimation?

Sublimation is the direct conversion of solid into a vapour state. Examples of substances having sublimation property are dry ice, iodine,naphthalene, camphor etc.

Fractional crystallisation

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This is a process used in the purification of organic compounds. Suppose there are two solids with different solubilities. And they are soluble in the same solvent, then fractional crystallisation is used to separate them.

3-phenyl prop-2-enoic acid is the IUPAC name of

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Cinnamic acid

What is the IUPAC name of urea?

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1-amino methanamide

which is the acid obtained when P4O10 is dissolved in cold water?

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metaphosphoric acid, HPO₃

Give the formula for oleum

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H₂S₂O₇

What is oleum?

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Fuming sulphuric acid

What is the commercial name for sodium hexametaphosphate?

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Calgon

Superphosphate of lime

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Ca(H₂PO₄)₂ + CaSO₄

Define acid & base according to lewis theory

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According to Lewis theory, an acid is an electron pair acceptor & base is an electron pair donor.

What do you mean by etching?

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An example of silicate material is glass. Remember that silica is represented as SiO₂.So compounds containing silica & silicates are attacked by hydrogen fluoride gas or its aqueous solution. When reacted with HF gas, SiF₄ gas is evolved. This is represented as

SiO₂ + 4HF--->2H₂O + SiF₄.

But in solutions H₂SiF₆ is formed. This is given as

SiO₂ + 6HF----> H₂SiF₆ + 2H₂O.

Etching means the attack of HF on glass.

Hydrogen diffuses faster than chlorine. why?

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This is based on graham's law of diffusion. That means gases with low molecular weight or low density diffuses fast. In the case of hydrogen molecular weight is 2 & for chlorine gas it is 71. So hydrogen diffuses more faster than chlorine.

What is fenton's reagent?

2010-09-05T22:43:00.000-07:00

Fenton's reagent is a mixture of Fe²⁺ & H₂O₂.

When comparing p-nitrophenol & o-nitrophenol which is a stronger acid & why?

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p-nitrophenol is a stronger acid than o-nitrophenol. This is because in o-nitrophenol intramolecular hydrogen bonding is present which makes o-nitrophenol a weaker acid.

Li resembles Mg in properties although they belong to different groups. Why?

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This is because of diagonal relationship. Also they have the same atomic size.

In fire extinguishers CCl4 is used. why?

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The important property of CCl₄ vapours is that they are non-inflammable. Due to this property they are used in fire extinguishers.

Concentrated nitric acid turns skin yellow. why?

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This is because concentrated nitric acid converts protein into yellow xanthoproteic acid & so the skin turns yellow.
Nitric acid is represented as HNO₃.

Orthophosphoric acid is tribasic but phosphorous acid is dibasic. why?

2010-09-05T22:09:00.000-07:00

Orthophosphoric acid is H₃PO₄ & phosphorous acid is H₃PO₃.
In orthophosphoric acid there are three hydrogen atoms linked to oxygen atoms but in phosphorous acid there are two hydrogen atoms bonded to oxygen atoms while the third hydrogen atom is directly linked to phosphorous. So orthophosphoric acid is tribasic & phosphorous acid is dibasic.