mole concept

Two elements A and B combine to form compound X and Y. For the fixed mass of A, masses of B combined for the compounds X and Y are in 3:7 ratio. If in compound X, 4g of A combines with 12g of B, then in compound Y, 8g of A combines with..............g of B.

• 24

• 56

• 28

• 8

If isotopic distribution of C¹² and C¹⁴ is 98% and 2%, respectively, then the number of C¹⁴ atoms in 12g of carbon is

• 1.032 * 10²²

• 1.20* 10²²

• 5.88* 10²³

• 6.02*10²³

What should be the density of an aqueous solutionof urea(molar mass=60g/mol) such that the molality as well as molarity of the solution becomes equal to unity?

• 1.0g/ml

• 1.6g/ml

• 1.06g/ml

• 1.16g/ml

A volume of 500 ml of a 0.1 M solution of AgNO₃ is added to 500ml of 0.1 M solution of KCl. The concentration of nitrate ion in the resulting solution is

• 0.05 M

• 0.1 M

• 0.2 M

• Reduced to zero

How much BaCl₂ would be needed to make 250ml of a solution having the same concentration of Cl^- as one containing 3.78g NaCl per 100 ml? (Ba=137)

• 16.8g

• 67.2 g

• 33.6g

• 22.4g

How many grams of solute should be added to 100g water to get a solution of density 1.2g/ml and strength 5%(w/v)?

• 5g

• 6g

• 4.75g

• 4.35g

A gaseous alkane is exploded with oxygen. The volume of O₂ for complete combustion to volume of CO₂ formed is in 7:4 ratio. The molecular formula of alkane is

• CH₄

• C₃H₈

• C₂H₆

• C₄H₁₀

Large amount of ammonia are burnt in the presence of a platinum catalyst to give nitric oxide, as the first step in the preparation of nitric acid.

NH₃(g) + O₂(g) ----------> NO(g) +H₂O(g)

Suppose a vessel contains 0.12moles of NH₃ and 0.14 moles of O₂. How many moles of NO may be obtained?

• 0.12

• 0.11

• 0.13

• 0.10

An organic compound contains 40% carbon and 6.67% hydrogen by mass. Which of thr following represents the empirical formula of the compound?

• CH₂

• CH₂O

• C₂H₄O

• CH₃O

The percentage of Fe(III) present in iron ore Fe_0.93O_1.00 is(Fe=56)

• 94

• 6

• 21.5

• 15