laboursonline – MCQs, Mock Tests | IIT JEE IIT JEE Atoms Molecules And Chemical Arithmetic

If atomic mass of oxygen were taken as 100 the molecular mass of water would be Approximately

1. 6.25
2. 112.5
3. 102
4. 106.25.

✅ Correct Answer: 2

Among the pairs of compounds given below which pair contains compounds with different percentage of carbon?.

1. propene and propane
2. butane and isobutene
3. acetylene and benzene
4. propene cyclopropane

✅ Correct Answer: 1

The balancing of chemical equation is based upon.

1. Law of combining volumes
2. Law of multiple proportions
3. Law of conservation of mass
4. Law of definite proportion

✅ Correct Answer: 3

If specific heat of certain element is 0.064. Its approximate atomic mass is200

1. 100
2. 10
3. 20
4. 200

✅ Correct Answer: 1

The compound AB contains elements A and B in the ratio of 1:35.5 by mass. The mass of B that will be required to react with 2 g of A is

1. 7.1 g
2. 3.55 g
3. 71 g
4. 35.5 g.

✅ Correct Answer: 1

0.6 mol of barium chloride in solution is mixed with 0.2 mol of sodium phosphate the amount of barium phosphate produced is

1. 0.1 mol
2. 0.3 mol
3. 0.4 mol
4. 0.5 mol.

✅ Correct Answer: 1

The mole fraction of solute in 1 molal aqueous solution is

1. 0.0176
2. 1.8
3. 0.05
4. 0.98.

✅ Correct Answer: 1

If given sample of potassium chlorate is 80% pure then 48 g of oxygen would be produced from

1. 98.0 g of the sample
2. 153.12 g of sample
3. 245 g of sample
4. 122.5 g of sample.

✅ Correct Answer: 2

A mixture of sand and naphthalene can be separted by.

1. Fractional crystallisation
2. Chromatography
3. Gravity separation
4. Sublimation

✅ Correct Answer: 4

27 g of aluminium will react completely with

1. 8 g of oxygen
2. 24 g of oxygen
3. 16 g of oxygen
4. 48 g of oxygen.

✅ Correct Answer: 2

Which of the following best explains the law of conservation of mass?

1. No change in mass is observed when 2.0 g of Mg is heated in vacuum
2. 1.2 g of carbon when burnt in excess if oxygen consumes only 3.2 g of it to form 4.4 g of carbon dioxide
3. 12 g of carbon when heated in limited supply of air produces only 20 g of carbon monoxide
4. A sample of air in heating does not show any change in mass but volume increases.

✅ Correct Answer: 2

Vapour density of a metal chloride is 77. The equivalent mass is 3. Its atomic mass would be

1. 3
2. 6
3. 9
4. 12

✅ Correct Answer: 4

276 g of silver carbonate on being strongly heated yields a residue weighing.

1. 2.16 g
2. 3.0 g
3. 6.2 g
4. 2.48 g

✅ Correct Answer: 1

Which of the following does not have same number of atoms?

1. 1 g of oxygen and 1 gm-atom of hydrogen
2. 1 g of oxygen and 1 gm of ozone
3. 1 g of hydrogen and 1 gm-atom of hydrogen
4. 4 g of calcium and 0.1 gm-atom of calcium.

✅ Correct Answer: 1

The correctly reported difference of 18.3426 and 8.06 willhave significant figures equal to

1. three
2. four
3. five
4. six.

✅ Correct Answer: 2

Which of the following does not have same percentage ofcarbon as in ethane?

1. 2-Butene
2. Cyclohexane
3. Cylohexne
4. 2-Methyl but-2ene.

✅ Correct Answer: 3

The percentage of hydrogen in water and hydrogen peroxide is11.1 and 5.9% respectively. These figures illustrate

1. Law of multiple proportions
2. Law of conservation of mass
3. Law of reciprocal proportions
4. Law of combining volumes.

✅ Correct Answer: 1

The number of moles of lead nitrate which are required to be decomposed to produce 48 of Oxygen

1. 3 mol
2. 1.5 mol
3. 0.15 mol
4. 0.3 mol.

✅ Correct Answer: 1

30 mL of an acid is neutralized by 15 mL of 0.2 N alkali. The strength of the acid is

1. 0.1 N
2. 0.2 N
3. 0.3 N
4. 0.4.

✅ Correct Answer: 1

The compounds with identical crystal structures and analogouschemical formulae are calledallotropes.

1. allotropes
2. isotones
3. isotones
4. isomorphs

✅ Correct Answer: 4

12 g of Mg (at. Mass 24) react with dilute mineral acid to produce maximum hydrogen equal to

1. 0.5 mol
2. 1.5 mol
3. 1.5 g
4. 1 g-atom.

✅ Correct Answer: 1

The conversion of oxygen to ozone occurs to the extent of 15% only. The mass of ozone that can be prepared from 67.2 L of oxygen at N.T.P. will be

1. 14.4 g
2. 96 g
3. 640 g
4. 64 g.

✅ Correct Answer: 1

Which of the following illustrates the law of conservation of mass?

1. Mixing of 10 g of sulphur and 2 g of sand does not show a change in mass
2. The mass of platinum wire before and after heating remains constant
3. 2.2 g of propane and 8 g of oxygen produces 10.2 g of gaseous mixture
4. 2.8 g of CO and 1.6 g of oxygen gave only 2.24 L of CO2 at S.T.P.

✅ Correct Answer: 3

142 g of chlorine represents

1. Two g-molecules of chlorine
2. 4 moles of chlorine atoms
3. Two moles of Cl atoms
4. Both a b.

✅ Correct Answer: 4

The mass of 60% HCl required for the neutralization of 10 L of 0.1 M KOH is

1. 60.8 g
2. 21.9 g
3. 100 g
4. 219 g.

✅ Correct Answer: 1

The mass of 60% HCl required for the neutralization of 10 L of 0.1 M KOH is

1. 60.8 g
2. 21.9 g
3. 100 g
4. 219 g.

✅ Correct Answer: 3

On dividing 0.86 by 16.564 the actual answer is 0.0519198. The correctly reported answer will be

1. 0.05
2. 0.051
3. 0.0519
4. 0.05191.

✅ Correct Answer: 2

Which one of the following solution of sulphuric acid will exactly neutralize 25 ml of 0.2 M NaOH solution?

1. 12.5 ml of 0.1 M solution
2. 25 ml of 0.2 M solution
3. 25 ml of 0.1 M solution
4. 50 ml of 0.2 M solution.

✅ Correct Answer: 1

A certain gaseous mixture contains methane and sulphur dioxide in ratio of 1: 8 by mass. The ration of the number of molecules is

1. 1:08
2. 1:02
3. 1:01
4. 2:01

✅ Correct Answer: 2

The volume of oxygen required for complete combustion of 20 ml of ethane is

1. 30 ml
2. 60 ml
3. 40 ml
4. 50 ml.

✅ Correct Answer: 2

Sodium carbonate crystals lose water molecules on exposure to atmosphere. The related property is called.

1. Deliquescence
2. Fluorescence
3. Efflorescence
4. Luminescence

✅ Correct Answer: 3

The number of moles of oxygen in one litre of air (21% oxygen by volume) at S.T.P. would be

1. 0.186 mol
2. 0.21 mol
3. 2.10 mol
4. 0.0093 mol.

✅ Correct Answer: 4

4 g of hydrogen is ignited with 4 g of oxygen the amount of water Formed is

1. 2.5 g
2. 0.5 g
3. 4.5 g
4. 8 g.

✅ Correct Answer: 3

The molality of a solution containing 5 g of sodium hydroxide in 250 g of solution

1. 0.5 m
2. 1.0 m
3. 2.0 m
4. 0.1 m.

✅ Correct Answer: 1

The number of moles of sodium oxide present in 620 g of it are

1. 1 mol
2. 10 mol
3. 18 mol
4. 100 mol.

✅ Correct Answer: 2

On rendering anhydrous the sample of hexahydrate calcium (II) chloride loses

1. 39.4% of its mass
2. 49.3% of its mass
3. 46.5% of its mass
4. 43.9% of its mass.

✅ Correct Answer: 2

The molarity of the solution containing 2.8% mass-volume solution of KOH is

1. M/10
2. M/2
3. M/5
4. 1 M.

✅ Correct Answer: 2

The number of atoms is largest in

1. 71 g of chlorine
2. 48 g of magnesium
3. 127 g of iodine
4. 4 g of hydrogen.

✅ Correct Answer: 4

Which of following acid can show optical isomerism?

1. 2 2-Dimathylpropanoic acid
2. 2-Methylpropanoic acid
3. 2-Methylbutanoic acid
4. Ethanoic acid.

✅ Correct Answer: 3

The mole fraction of water in a solution containing 117 g sodium chloride and 900 g of water is

1. 0.0632
2. 0.038
3. 0.9615
4. 1.000.

✅ Correct Answer: 3

During synthesis of ammonia from its constituent elements the volume of the product relative to the total volume of thereacting species is.

1. one-fourth
2. three-fourth
3. one-half
4. one-eighth

✅ Correct Answer: 3

50 ml of samples of distilled water ordinary tap water and boiled tap water requires 2 ml 26 and 10 of soap solution respectively to form permanent lather. The ratio of permanent hardness to temporary hardness in tap water is

1. 1:02
2. 3:02
3. 2:00
4. 2:01

✅ Correct Answer: 1

The number of moles of NaCl in 3 L of 3 M NaCl solution is

1. 1
2. 3
3. 9
4. 6

✅ Correct Answer: 3

The mole fraction of solute in 1 molal aqueous solution is

1. 0.0177
2. 1.8
3. 0.05
4. 0.98

✅ Correct Answer: 1

27 g of Al will completely react with.

1. 3 mol of oxygen
2. 3 g-atoms of oxygen
3. 3 g-equivalents of oxygen
4. 3 atoms of oxygen

✅ Correct Answer: 3

The density of chlorine relative to air is.

1. 3
2. 2.46
3. 4
4.

✅ Correct Answer: 2

When 4.0 g of iron is burnt at high temperature to ferric oxide at constant pressure 29.28 kJ Of heat is evolved. The amount of heat evolved for producing one mole of ferric oxide is

1. 819.84 kJ
2. 40.99 kJ
3. 81.98 kJ
4. 409.9 kJ.

✅ Correct Answer: 4

33.6 L of water vapour at S.T.P. are condensed to liquid state. The volume occupied by it is approximately.

1. 1 L
2. 18 ml
3. 27 L
4. 127 ml

✅ Correct Answer: 3