Hydrogen combines directly with:

(a) Ca

(b) Cu

(c) Zn

(d) Fe

Acidified solution of chromic acid on treatement with H₂O₂ yields :

(a) ${\mathrm{CrO}}_3 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{O}}_2$

(b) ${\mathrm{Cr}}_2{\mathrm{O}}_2 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{O}}_2$

(c) ${\mathrm{CrO}}_5 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{K}}_2{\mathrm{SO}}_4$

(d) ${\mathrm{H}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7 + {\mathrm{H}}_2\mathrm{O} + {\mathrm{O}}_2$

The ortho and para hydrogen possess:

(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

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