Assertion (A): Dry hydrogen chloride gas is collected by the upward displacement of air.

Reason (R): Hydrogen chloride gas is lighter than air.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true

The structures of four hydrocarbons are shown below:

How many isomers of butene are there?

1. 1
2. 2
3. 3
4. 4

₁H² is an isotope of hydrogen. In the modern Periodic Table it will:

1. be placed before hydrogen
2. be placed after hydrogen
3. be placed at the same position as hydrogen
4. not have any position in the Periodic Table

A nitrate which forms a precipitate with ammonium hydroxide and is also soluble in excess of it:

1. ferrous nitrate
2. ferric nitrate
3. lead nitrate
4. copper nitrate