Choose the wrong statement from the following 

• The 'silver' UK coins are made of Ag/ Ni alloy 

• TiO₂ is used in the pigment industry

• MnO₂ is used in the dry battery cells

• V₂O₅ catalyses the oxidation of SO₂ in the manufacture of sulphuric acid

The standard enthalpy of formation of H₂O (l) and Fe₂O₃ (s) are respectively -286 kJ mol^-1 and -824 kJ mol^-1. What is the standard enthalpy change for the following reaction?

Fe₂O₃ (s) + 3H₂ (g) → 3H₂O (l) + 2Fe (s)

• -538 kJ mol^-1

• +538 kJ mol^-1

• -34 kJ mol^-1

• +34 kJ mol^-1

The correct descending order of the heat liberated (in kJ) during the neutralisation of the, acids CH₃COOH (W), HF (X), HCOOH (Y) and HCN (Z) under identical conditions (K_a of CH₃COOH = 1.8 × 10^-5, HCOOH =1.8 × 10^-10 HCN = 4.9 × 10^-10 and HF = 3.2 × 10^-4)

• Y > X > Z > W

• X > Y > W > Z

• W > X > Y > Z

• Z > W > Y > X

How many times a 0.1 M strong monobasic acid solution should be diluted so that pH of the resulting solution is tripled?

• 50

• 10

• 25

• 100

The equilibrium pressure for the given reaction, is  $\mathrm{\pi }$/4 atm at 400 K. The K_p for the given reaction (in atm²) is

MSO₄.2H₂O (s) $\rightleftharpoons$ MSO₄ (s) + 2H₂O (g)

• ${\mathrm{\pi }}^2 / 4$

• $\mathrm{\pi } / 6$

• ${\mathrm{\pi }}^2 / 16$

• $\mathrm{\pi } / 16$

Calculate the molality of a solution that contains 51.2 g of naphthalene (C₁₀H₈) in 500 mL of carbon tetrachloride. The density of CCl₄ is 1.60 g/mL

• 0.250 m

• 0.500 m

• 0.750 m

• 0.840 m

Thermal decomposition of ammonium dichromate gives

• N₂, H₂O and Cr₂O₃

• N₂, NH₃ and CrO

• (NH₄)₂CrO₄ and H₂O

• N₂, H₂O and CrO₃

In the hydrogen atom spectrum, the emission of the least energetic photon takes place during the transition from n = 6 energy level to n = .......... energy level.

• 1

• 3

• 5

• 4

9.

When 2.46 gm of a hydrated salt (MSO₄xH₂O) is completely dehydrated, 1.20 gm of anhydrous salt is obtained. If the molecular weight of anhydrous salt is 120 gm mol^-1, what is the value of x?

• 2

• 7

• 4

• 6

Identify the T-shaped molecule from the following.

• BF₃

• NH₃

• NF₃

• CIF₃