Which of the following element shows maximum valency ?

• Carbon

• Barium

• Nitrogen

• Sulphur

The volume of oxygen necessary for the complete combustion of 20 L of propane is :

• 40 L

• 60 L

• 80 L

• 100 L

0.005 M acid solution has 5 pH. The percentage ionisation of acid is :

• 0.8%

• 0.6%

• 0.4%

• 0.2%

CH₃COOH is weaker acid than H₂SO₄.It is due to:

• more ionization

• less ionization

• covalent bond

• electrovalent bond

The compressibility factor of an ideal gas is :

• 1

• 2

• 4

• 0

A gaseous mixture contains 56 g of N₂, 44 g of CO₂ and 16 g of CH₄. The total pressure of mixture is 720 mm of Hg. The partial pressure of methane is :

• 75 atm

• 160 atm

• 180 atm

• 215 atm

The metal used to recover copper from a solution of CuSO₄ is :

• Fe

• He

• Na

• Ag

The solubility of Sb₂S₃ in water is 1.0 × 10^-5 mol/L at 298K. What will be its solubility product?

• 108 × 10^-25

• 1.0 × 10^-25

• 144 × 10^-25

• 126 × 10^-24

What will be the pH value of 0.05 M Ba(OH)₂ solution?

• 12

• 13

• 1

• 12.96

20.

Which of the following elements never show positive oxidation number?

• O

• Fe

• Ga

• F