On bubbling CO₂ through a solution of barium peroxide in water:

(1) O₂ is formed

(2) H₂CO₃ is formed

(3) H₂O₂ is formed

(4) H₂ is formed

A mixture of hydrazine and 60 to 90 percent of H₂O₂ solution is:

(a) antiseptic

(b) rocket fuel

(c) germicide

(d) insecticide

A given solution of H₂O₂ is 30 volume. Its concentration in terms of molarity is:

(a) 9.1 M

(b) 2.68 M

(c) 2.5 M

(d) 26.8 M

Decomposition of H₂O₂ is accelerated by:

(a) traces of acids

(b) finely divided metals

(c) acetanilide

(d) alcohol

Which method cannot be used to remove hardness of water ?

(1) Clark's method

(2) By adding washing soda

(3) Calgon process

(4) Filtration

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

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) ${\mathrm{Fe}}^{1+} \stackrel{ }{\to }{\mathrm{Fe}}^{3+}$ (alkaline medium)

(4) $\mathrm{KI} \stackrel{ }{\to }{\mathrm{I}}_2$

H₂O₂ restores the colour of old lead paintings, blackened by the action of H₂S gas, by:

(1) converting PbO₂ to Pb

(2) oxidising PbS to PbSO₄

(3) converting PbCO₃ to Pb

(4) oxidizing PbSO₃ to PbSO₄

(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

(a) oxidising in (I) and reducing in (II)

(b) reducing in (I) and oxidising in (II)

(c) reducing in(I) and  (II)

(d) 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

(a) +5

(b) +3

(c) +6

(d) -10