A colourless crystalline salt 'x' is soluble in dilute HCl. On adding NaOH solution, it gives a white precipitate which is insoluble in excess of NaOH. 'x' is

• Al₂(SO₄)₃

• ZnSO₄

• MgSO₄

• SnCl₂

Which metal is used to make alloy steel for armour plates, safes and helmets?

• Al

• Mn

• Cr

• Pb

Enthalpy of formation of HF and HCl are -161 kJ and -92 kJ respectively. Which of the following statements is incorrect?

• HCl is more stable than HF

• HF and HCl are exothermic compounds

• The affinity of fluorine to hydrogen is greaterthan the affinity of chlorine to hydrogen

• HF is more stable than HCl

4.

Heat liberated with 100 mL of 1 N NaOH is neutralised by 300 mL of 1 N HCl

• 11.56 kJ

• 5.73 kJ

• 22.92 kJ

• 17.19 kJ

The enthalpies of formation of Al₂O₃ and Cr₂O₃ are -1596 kJ and -1134 kJ respectively. $∆$H for the reaction,

2Al + Cr₂O₃  → 2Cr+ Al₂O₃ is

• -2730 kJ

• -462 kJ

• -1365 kJ

• +2730 kJ

The gaseous reaction

A + B $\rightleftharpoons$ 2C + D + Q is most favoured at

• low temperature and high pressure

• high temperature and high pressme

• high temperature and low pressure

• low temperature and low pressure

The volume of water to be added to $\frac{\mathrm{N}}{2}$ to prepare 500 mL of $\frac{\mathrm{N}}{10}$ solution is

• 450 mL

• 100 mL

• 45 mL

• 400 mL

The equivalent weight of a certain trivalent element is 20. Molecular weight of its oxide is

• 152

• 56

• 168

• 68

Solubility product of a salt AB is 1 × 10^-8 in a solution in which concentration of A is 10^-3 M. The salt will precipitate when the concentration of B becomes more than

• 10^-4 M

• 10^-7 M

• 10^-6 M

• 10^-5 M

The percentage s-character of the hybrid orbitals in methane, ethene and ethyne are respectively

• 25, 33, 50

• 25, 50, 75

• 50, 75, 100

• 10, 20, 40