When substance A reacts with water, it produces a combustible gas B and a solution of substances 'C' in water. When another substance 'D' reacts with this solution of C, it produces the same gas 'B' on warming but 'D' can produce gas 'B' on reaction with dilute sulphuric acid at room temperature. 'A' imparts a deep golden yellow colour to a smokeless flame of a bunsen burner. A, B, C and D respectively are -

1. $\mathrm{Na},$ ${\mathrm{H}}_2,$ $\mathrm{NaOH},$ $\mathrm{Zn}$                              

2. $\mathrm{K},$ ${\mathrm{H}}_2,$ $\mathrm{KOH},$ $\mathrm{Al}$

3. $\mathrm{Ca},$ ${\mathrm{H}}_2,$ $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2,$ $\mathrm{Sn}$                           

4. ${\mathrm{CaC}}_2,$ ${\mathrm{C}}_2{\mathrm{H}}_2,$ $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2,$ $\mathrm{Fe}$

The colour of hydrogen is –

1. Blue                           

2. Yellow

3. Orange                       

4. No colour

The correct statement among the following regarding hydrogen is–

1. It can form a bond in +1 as well as –1 oxidation state

2. It is always collected at the cathode

3. It has a very low ionization potential

4. It has the same electronegativity as halogens

The reaction of aqueous KMnO₄ with H₂O₂ in acidic condition gives:
1. $M{n}^{4+}$ $and$ $O_2$
2. $M{n}^{2+}$ $and$ $O_2$
3. $M{n}^{2+}$ $and$ $O_3$
4. $M{n}^{4+}$ $and$ $Mn{O}_2$

The method used to remove the temporary hardness of water is-

1. Synthetic resins method

2. Calgon's method

3. Clark's method

4. Ion-exchange method

The incorrect statement among the following regarding hydrogen is -

1. Hydrogen never acts as a cation in Ionic salts

2. Hydronium ion, H₃O⁺, exists freely in a solution

3. Dihydrogen does not act as a reducing agent

4. Hydrogen has three isotopes of which Protium is the most common

${\mathrm{H}}_2{\mathrm{O}}_2$ act as a reducing agent in :

1. Reaction with a ferrous salt.

2. Reaction with iodides.

3. Reaction with lead sulphide.

4. Reaction with ${\mathrm{KMnO}}_4$ in an acid medium.

The correct statement among the following regarding H₂O₂ is-

1. Two hydrogen atoms are connected to one oxygen atom.

2. All the four atoms are in the same plane.

3. The four atoms are arranged in a non-linear and non-planar manner.

4. O-H bonds are polar but the molecule is non-polar.

 Covalent hydride among the following is -

1. ${\mathrm{NH}}_3$ $\mathrm{and}$ ${\mathrm{B}}_2{\mathrm{H}}_6$

2. ${\mathrm{CaH}}_2$ $\mathrm{and}$ ${\mathrm{B}}_2{\mathrm{H}}_6$

3. $\mathrm{NaH}$ $\mathrm{and}$ ${\mathrm{CaH}}_2$

4. $\mathrm{NaH}$ $\mathrm{and}$ ${\mathrm{NH}}_3$

A compound that acts as both reducing and oxidising agent is-

1. H₂SO₄

2. H₂O₂

3. KOH

4. KMnO₄