Blackened oil planting can be restored into original form by the action of:

1. Chlorine

2. ${\mathrm{BaO}}_2$

3. ${\mathrm{H}}_2{\mathrm{O}}_2$

4. ${\mathrm{MnO}}_2$

Which of the following statement regarding ${\mathrm{H}}_2{\mathrm{O}}_2$ is wrong.

(1) It is stable in acid medium

(2) It acts as oxidising as well as reducing agent

(3) It has zero dipole moment

(4) Pure ${\mathrm{H}}_2{\mathrm{O}}_2$ is slightly acidic

Polyphosphates are used as water softening agents because they –

(1) form soluble complexes with anionic species

(2) precipitate anionic species

(3) form soluble complexes with cationic species

(4) precipitate cationic species

The ortho and para hydrogen have –

(A) Same physical properties but different chemical properties

(B) Different physical properties but same chemical properties

(C) Same chemical and physical properties

(D) Different physical and chemical properties

Permanent hardness of water can be removed, by adding –

(1) Soda lime

(2) Sodium bicarbonate

(3) Washing soda

(4) Sodium chloride

The correct increasing order of the acidity of ${\mathrm{CO}}_2, {\mathrm{H}}_2\mathrm{O} \mathrm{and} {\mathrm{H}}_2{\mathrm{O}}_2$ is $-$

(1) ${\mathrm{CO}}_2<{\mathrm{H}}_2{\mathrm{O}}_2<{\mathrm{H}}_2\mathrm{O}$                         

(2) ${\mathrm{H}}_2\mathrm{O}<{\mathrm{H}}_2{\mathrm{O}}_2<{\mathrm{CO}}_2$

(3) ${\mathrm{H}}_2\mathrm{O}<{\mathrm{H}}_2{\mathrm{O}}_2>{\mathrm{CO}}_2$                         

(4) ${\mathrm{H}}_2{\mathrm{O}}_2>{\mathrm{CO}}_2>{\mathrm{H}}_2\mathrm{O}$

Metal which does not react with cold water but evolves H₂ with steam is –

(1) Na                           

(2) K

(3) Pt                             

(4) Fe

The oxidation states of the most electronegative element in the products of the reaction between ${\mathrm{BaO}}_2$ with dil. ${\mathrm{H}}_2{\mathrm{SO}}_4$ are–

1. 0, and –1                                   

2. –1, and –2

3. –2, and 0                                     

4. –2, and + 1

Hardness of water is due to presence of salts of –

(1) ${\mathrm{Na}}^{+} \mathrm{and} {\mathrm{K}}^{+}$                                  

(2) ${\mathrm{Ca}}^{2+} \mathrm{and} {\mathrm{Mg}}^{2+}$

(3) ${\mathrm{Ca}}^{2+} \mathrm{and} {\mathrm{K}}^{+}$                                

(4) ${\mathrm{Ca}}^{2+} \mathrm{and} {\mathrm{Na}}^{+}$

Ice melts at a temperature lower than its usual melting point when the pressure is increased. This is because-

1. Ice has less density than water

2. Pressure generates heat

3. The chemical bonds break under pressure

4. Ice is not a true solid