Another name for chlorobenzene

Phenyl chloride

Alkenes & Alkynes

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

Main source of alkanes

Petroleum is considered as the main source of alkanes.

Paraffins

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

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

Borax

Borax is represented by the formula Na₂B₄O₇.10H₂O

Water sterilisation

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

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

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

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

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

Biogas

Siemens gas

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

• Fuel
• Reducer
• Manufacture of methanol

Water gas

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

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

• 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

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

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

Molality & Molal solution

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.