On adding which of the following, the pH of 20 mL of 0.1 N HCl will not alter?

• 20 mL of distilled water

• 1 mL of 0.1 N NaOH

• 500 mL of HCl of pH =1

• 1 mL of 1 N HCl

452.

The equivalent mass of a certain bivalent metal is 20. The molecular mass of its anhydrous chloride is

• 111

• 55.5

• 75.5

• 91

The approximate time duration in hours to electroplate 30 g of calcium from molten calcium chloride using a current of 5 A is [At. mass of Ca = 40]

• 80

• 10

• 16

• 8

1.78 g of an optically active L-amino acid (A) is treated with NaNO₃/ HCl at 0°C. 448 cm³ of nitrogen was at STP is evolved. A sample of protein has 0.25% of this amino acid by mass. The molar mass of the protein is

• 36500 g mol^-1

• 34500 g mol^-1

• 35400 g mol^-1

• 35600 g mol^-1

10 g of a mixture of BaO and CaO requires 100 cm³ of 2.5 M HCl to react completely. The percentage of calcium oxide in the mixture is approximately (Given: molar mass of BaO = 158)

• 52.6

• 55.1

• 44.9

• 47.4

Impure copper containing Fe, Au, Ag as impurities is electrolytically refined. A current of 140 A for 482.5 s decreased the mass of the anode by 22.26 g and increased the mass of cathode by 22.011 g. Percentage of iron in impure copper is (Given molar mass Fe = 55.5 g mol^-1, molar mass Cu = 63.54 g mol^-1)

• 0.95

• 0.85

• 0.96=7

• 0.90

25 cm³ of oxalic acid completely neutralised 0.064 g of sodium hydroxide. Molarity of the oxalic acid solution is

• 0.064

• 0.045

• 0.015

• 0.032

5.5 mg of nitrogen gas dissolves in 180 g of water at 273 K and 1 atm pressure due to nitrogen gas. The mole fraction of nitrogen in 180 g of water at 5 atm nitrogen pressure is approximately

• 1 × 10^-6

• 1 × 10^-5

• 1 × 10^-3

• 1 × 10^-4

50 cm³ of 0.04 M K₂Cr₂O₇ in acidic medium oxidises a sample of H₂S gas to sulphur. Volume of 0.03 M KMnO₄ required to oxidize the same amount of H₂S gas to sulphur, in acidic medium is 

• 60 cm³

• 80 cm³

• 90 cm³

• 120 cm³

0.06% (w/V) aqueous solution of urea is isotonic with

• 0.06% glucose solution

• 0.6% glucose solution

• 0.01M glucose solution

• 0.1M glucose solution