Hydrogen gas is generally prepared by the

1

(a)

reaction of granulated zinc with dilute H₂SO₄

(b)

reaction of zinc with conc. H₂SO₄

(c)

reaction of pure zinc with dil. H₂SO₄

(d)

action of steam on red hot coke.

Hydrogen peroxide is used as

1

(a)

an oxidizing agent

(b)

a reducing agent

(c)

a bleaching agent

(d)

all of the above

Water may be softened using

1

(a)

sodium aluminium silicate

(b)

Graham's salt

(c)

an ion exchange resin

(d)

trisodium phosphate

On treatment of hard water with zeolite, sodium ions get exchanged with

1

(a)

Ca²⁺ ions

(b)

Mg²⁺ ions

(c)

H⁺ ions

(d)

OH^-

Calgon, which is used as a water softener, has the formula

1

(a)

Na₄ [Na₂ (PO₃)₆]

(b)

Na₂ [Na₄(PO₃)₆]

(c)

Na₂ [Na₄(PO₄)₅]

(d)

Na₂ [Na₂ (PO₄)₆]

Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

1

(a)

Hydrogen atom has only one electron in its 1s-orbital. So, to achieve stable inert gas configuration of helium, it exists as diatomic molecule and is called dihydrogen.

Name the isotope of hydrogen which contains equal number of protons and neutrons.

1

(a)

Deuterium ( \(_{ 1 }^{ 2 }{ H }\))
Number of protons (p) = number of electrons
= atomic number = 1
Number of neutrons (n) = Mass number - atomic number
= 2 - 1 = 1

Which isotope of hydrogen is radioactive?

1

(a)

Tritium \(\left({ }_{1}^{3} \mathrm{H}\right)\) is radioactive because neutron/proton ratio is more than 1.5.

Name the compound each in which hydrogen exists in negative oxidation state

1

(a)

NaH, here oxidation state of hydrogen is -1.

Name the compound each in which hydrogen exists in positive oxidation state

1

(a)

HCl, here oxidation state of hydrogen is +1.

Write the Lewis structure of hydrogen peroxide.

1

(a)

the Lewis structure of hydrogen peroxide is

Which compounds cause temporary hardness of water?

1

(a)

Ca(HCO₃)₂ and Mg (HCO₃)₂

Name a substance which can oxidise H₂O₂.

1

(a)

Acified KMnO₄.

Name the phenomenon of adsorption of hydrogen on metal surface.

1

(a)

Occlusion.