Among the following molecules

(i) $\stackrel{..}{\mathrm{X}}$eO₃ (ii) $\stackrel{..}{\mathrm{X}}$eOF₄ (iii) $\stackrel{..}{\mathrm{X}}$eF₆ 

those having same number of lone pairs on Xe are

• (i) and (ii) only

• (i) and (iii) only

• (ii) and (iii) only

• (i), (ii) and (iii)

The diamagnetic species is

• [Ni(CN)₄]^2-

• [NiCl₄]^2-

• [CoCl₄]^2-

• [CoF₆]^2-

In diborane, the two H - B - H angles are nearly

• 60°, 120°

• 95°, 120°

• 95°, 150°

• 120°, 180°

${}_{92}{}^{238}\mathrm{U}$ emits 8 α-particles and 6 β-particles. The neutron/proton ratio in the product nucleus is

• 60/41

• 61/40

• 62/41

• 61/42

F₂ formed by reacting K₂MnF₆ with

• SbF₅

• MnF₃

• KSbF₆

• MnF₄

The isoelectronic pair is

• Cl₂O, ICl₂^-

• ICl₂^-, ClO₂

• IF₂⁺, I₃^-

• ClO₂^-, ClF₂⁺

α-Particles can be detected using

• thin aluminium sheet

• barium sulphate

• zinc sulphide screen

• gold foil

8.

$∆{\mathrm{H}}_{\mathrm{f}}^{°}$ (298 K) of methanol is given by the chemical equation

• CH_{4 (g)} + $\frac{1}{2}$O_{2 (g)} →CH₃OH_(g)

• C (graphite) + $\frac{1}{2}$O_{2 (g)} + 2H₂ → CH₃OH_(l)

• C (diamond) + $\frac{1}{2}$O_2(g) + 2H_2(g) → CH₃OH_(l)

• CO_(g) + 2H₂ → CH₃OH_(l)

An endothermic reaction with high activation energy for the forward reaction is given by the diagram

When 10 mL of 0.1 M acetic acid (pK_a = 5.0) is titrated against 10 ml of 0.1 M ammonia solution (pK_b = 5.0), the equivalence point occurs at pH

• 5.0

• 6.0

• 7.0

• 9.0