21.

Which of the following substance is not related with HVZ reaction?

• α-bromo acetic acid

• Zn/ Hg

• Cl₂

• Red P

The electronic configuration of an element C is 1s², 2s², 2p⁶. The formula of substance containing only C will be

• C₈

• C₄

• C₂

• C

Which of the following compound show acidic nature?

• but-1-yne

• but-2-yne

• but-1-ene

• buta-1, 3-diene

Kjeldahl trap is

• fitted over Kjeldahl flask

• used to trap water vapours

• used to trap ammonia

• None of the above

The hydration energy of Mg²⁺ ions is higher than that of

• Al³⁺

• Be²⁺

• Na⁺

• None of these

See the following redox reaction

A²⁺ + 2e^- → A; E° = +0.34 V

   A⁺ + e^- → A; E° = +0.52 V

Which ion is expected to be stable?

• A²⁺

• A⁺

• Both can form stable complexes

• None can form stable complexes

The first ionisation potential (in eV) of N and O atoms are

• 14.6, 13.6

• 13.6, 14.6

• 13.6, 13.6

• 14.6, 14.6

The dimensions of a unit cell of a crystal are a = 0.397, b = 0.387, c = 0.504 and α = β = 90°, γ = 120° the crystal system is

• cubic

• hexagonal

• orthorhombic

• rhombohedral

Which one of the following has minimum gold number?

• Starch

• Sodium oleate

• Gelatin

• Gum arabic

Which gas behaves abnormally when liquified?

• Xenon

• Krypton

• Helium

• Argon