Poorest reducing agent among following is

1. atomic hydrogen

2. nascent hydrogen

3. dihydrogen

4. all have same reducing strength

Which conversion is not done by H₂O₂ ?

1. ${\mathrm{Fe}}^{2+} \stackrel{ }{\to }{\mathrm{Fe}}^{3+}$(acidic medium)

2. $\mathrm{PbS}\stackrel{ }{\to }{\mathrm{PbSO}}_4$

3. ${\mathrm{Fe}}^{+} \stackrel{ }{\to }{\mathrm{Fe}}^{3+}$ (alkaline medium)

4. $\mathrm{KI} \stackrel{ }{\to }{\mathrm{I}}_2$

H₂O₂ restores the colour of old lead paintings by:

1. Converting PbO₂ to Pb

2. Oxidising PbS to PbSO₄

3. Converting PbCO₃ to Pb

4. Oxidizing PbSO₃ to PbSO₄

The correct statement for the hydrogenation of oil is:

(I) ${\mathrm{H}}_2{\mathrm{O}}_2+{\mathrm{O}}_3 \stackrel{ }{\to }{\mathrm{H}}_2\mathrm{O} + 2{\mathrm{O}}_2$

(II) ${\mathrm{H}}_2{\mathrm{O}}_2 + {\mathrm{Ag}}_2\mathrm{O} \stackrel{ }{\to }2\mathrm{Ag} + {\mathrm{H}}_2\mathrm{O} + {\mathrm{O}}_2$

Role of hydrogen peroxide in the above reactions is respectively

1. oxidising in (I) and reducing in (II)

2. reducing in (I) and oxidising in (II)

3. reducing in (I) and  (II)

4. oxidising in(I) and (II)

In acidic medium, H₂O₂ changes ${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}$ to CrO₅ which has two (-O-O-) bonds. Oxidation

state of Cr in CrO₅ is

1. +5

2. +3

3. +6

4. -10

The ease of adsorption of the hydrated alkali metal ions on an ion-exchange resins

follows the order:

1. Li⁺<K⁺<Na⁺<Rb⁺

2. Rb⁺<K⁺<Na⁺<Li⁺

3. K⁺<Na⁺<Rb⁺<Li⁺

4. Na⁺<Li⁺<K⁺<Rb⁺

In which reaction hydrogen is not formed ?

(1) Copper and hydrochloric acid

(2) Iron and sulphuric acid

(3) Magnesium and steam

(4) Sodium and alcohol

 Hardness of water cannot be removed by -

1. Clark's method

2. Adding washing soda

3. Calgon process

4. Filtration

The decomposition of H₂O₂ is accelerated by:

1. traces of acids

2. finely divided metals

3. acetanilide

4. alcohol