C₆H₆ + O₃ → X $\stackrel{\mathrm{Zn}/ {\mathrm{H}}_2\mathrm{O}}{\to }$ Y; X and Y are respectively.

• diozonide, glycol

• triozonide, glyoxalic acid

• triozonide, glyoxal

• monoozonide, oxalic acid

If the equilibrium constant for the reaction,

2AB  A₂ + B₂ 

is 49, what is the equilibrium constant for AB $$ \rightleftharpoons \frac{1}{2}{\mathrm{A}}_1 + \frac{1}{2}{\mathrm{A}}_2${\mathrm{}}_{}$ ? 

• 7

• $\frac{1}{7}$

• 24.5

• 49

The pH of 0.05 M acetic acid is K_a = 2 × 10^-5)

• 2

• 11

• 10^-3

• 3

What is the entropy change in JK^-1 during the melting of 27.3 g of ice at 0°C? (Latent heat of fusion of ice = 330 Jg^-1)

• 330

• 12.1

• 3.3

• 33

Identify the order in which the spin only magnetic moment (in BM) increases for the following four ions

(I) Fe²⁺

(II) Ti²⁺

(III) Cu²⁺

(IV) V²⁺

• I, II, IV, III

• IV, I, II, III

• III, IV, I, II

• III, II, IV, I

Which one of the following frequencies of radiation (in Hz) has a wavelength of 600 nm?

• 2.0 × 10¹³ 

• 5.0 × 10¹⁶ 

• 2.0 × 10¹⁴ 

• 5.0 × 10¹⁴ 

According to Bohr's theory which one of the following values of angular momentum of hydrogen atom is not permitted?

• $\frac{1.25 \mathrm{h}}{\mathrm{\pi }}$

• $\frac{\mathrm{h}}{\mathrm{\pi }}$

• $\frac{1.5 \mathrm{h}}{\mathrm{\pi }}$

• $\frac{0.5 \mathrm{h}}{\mathrm{\pi }}$

Which one of the following is correct order of second ionisation potential of Na, Ne, Mg and Al?

• Al < Na < Mg < Ne

• Ne < Al < Na < Mg

• Mg < Al < Ne < Na

• Na < Mg < Ne < Al

The formal charges of N₍₁₎, N₍₂₎ and O atoms in the following figure are respectively

• +1, -1, 0

• -1, +1, 0

• +1, +1, 0

• -1, -1, 0

In which of the following pairs, the central atoms have the same number of lone pairs of electrons?

• PCl₅, BrF₅

• XeF₂, ICl

• XeF₄, ClO${}_4^{-}$

• SCl₄, CH₄