The volume of neon gas in cm³ at STP having the same number of atoms as that present in 800 mg of Ca is (At. mass : Ca = 40 g mol^-1, Ne = 20 g mol^-1)

• 448

• 896

• 224

• 112

How many molecules of CO₂ are formed when one milligram of 100% pure CaCO₃ is treated with excess hydrochloric acid?

• 6.023 × 10²³

• 6.023 × 10¹⁸

• 6.023 × 10²¹

• 6.023 × 10²²

73.

5.0 g of sodium hydroxide (molar mass 40 g mol^-1) is dissolved in little quantity of water and the solution is diluted upto 100 ml. What is the molarity of the resulting solution?

• 0.1 mol dm^-3

• 1.0 mol dm^-3

• 0.125 mol dm^-3

• 1.25 dm^-3

The mole fraction of methanol is in 4.5 molal aqueous solution is

• 0.250

• 0.125

• 0.100

• 0.075

0.02 mole of [Co(NH₃)₅Br]Cl₂ and 0.02 mole of [Co(NH₃)₅Cl]SO₄ are present in 200 cc of a solution X. The number of moles of the precipitates Y and Z that are formed when the solution X is treated with excess barium chloride are respectively.

• 0.02, 0.02

• 0.01, 0.02

• 0.02, 0.04

• 0.04, 0.02

The maximum prescribed concentration of cadmium in drinking water in ppm is

• 0.05

• 3

• 2

• 0.005

A 100% pure sample of a divalent metal carbonate weighing 2 g on complete thermal decomposition releases 448 cc of carbon dioxide at STP. The equivalent mass of the metal is

• 40

• 20

• 28

• 12

A mixture of ethane and ethene occupies 41 L at 1 atm and 500 K. The mixture reacts completely with $\frac{10}{3}$mole of O₂ to produce CO₂ and H₂O. The mole fraction of ethane and ethene in the mixture are respectively (R = 0.082 L atm K^-1 mol^-1)

• 0.50, 0.50

• 0.75, 0.25

• 0.67, 0.33

• 0.25, 0.75

Molar heat capacity of aluminium is 25 JK^-1 mol^-1. The heat necessary to raise the temperature of 54 g of aluminium (atomic mass 27 g mol^-1) from 30°C to 50°C is

• 1.5 kJ

• 0.5 kJ

• 1.0 kJ

• 2.5 kJ

How much time (in hours) would it take to distribute one Avogadro number of wheat grains, if 10²⁰ grains are distributed each second?

• 0.1673

• 1.673

• 16.73

• 167.3