Some Basic Concepts of Chemistry

1. Suppose the elements X and Y combine to form two compounds XY₂ and X₃Y₂. If 0.1 mole of XY₂weighs 10 g and 0.05 mole of X₃Y₂ weighs 9 g, the atomic weight of X and Y respectively, will be:
1. 40, 30
2. 60, 40
3. 20, 30
4. 30, 20

2.

Which of the following is dependent on temperature?

1.	Molarity	2.	Mole fraction
3.	Weight percentage	4.	Molality

3. The maximum number of water molecules among the following is:
1. 18 mL of water
2. 0.18 g of water
3. 0.00224 L water vapours at 1 atm and 273 K
4. 10^-3mol of water

4.

If Avogadro number $N_{A}$, is changed from $6 . 022 \times \left(10\right)^{23}$$\text{mol}^{- 1}$ to $6 . 022 \times \left(10\right)^{20} ~\text{mol}^{- 1}$ this would change:

1.	The definition of mass in units of grams
2.	The mass of one mole of carbon
3.	The ratio of chemical species to each other in a balanced equation
4.	The ratio of elements to each other in a compound

5.

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g of magnesium oxide.
The percentage purity of magnesium carbonate in the sample is:
(Atomic weight of Mg=24)

1.	75	2.	96
3.	60	4.	84

6.

What is the mass of the precipitate formed when 50 mL of 16.9% solution of AgNO₃ is mixed with 50 mL of 5.8% NaCl solution? (Ag = 107.8, N = 14, O = 16, Na= 23, Cl = 35.5)
1. 28 g
2. 3.5 g
3. 7 g
4. 14 g

7.

Calculate the mole fraction of the solute in a 1.00 m aqueous solution.

1.	0.177	2.	0.771
3.	0.0534	4.	0.0177

8. The number of water molecules are maximum in:
1. 18 molecules of water
2. 1.8 g of water
3. 18 g of water
4. 18 moles of water

9.

A mixture of gases contains H₂ and O₂ gases in the ratio of 1 : 4 (w/w). The molar ratio of the two gases in the mixture will be:

1.	1:4	2.	4:1
3.	16:1	4.	2:1

10.

When 22.4 litres of H₂(g) is mixed with 11.2 litres of Cl₂(g), both at STP, the moles of HCl(g) formed is equal to:
1. 1 mol of HCl(g)
2. 2 mol of HCl(g)
3. 0.5 mol of HCl(g)
4. 1.5 mol of HCl(g)

11.

1.0 g of magnesium is burnt with 0.56 g O₂ in a closed vessel. Which reactant is left in excess and by how much? (At. wt. Mg = 24; O = 16)

1.	Mg, 0.16 g	2.	$O_{2}$ , 0.16 g
3.	Mg, 0.44 g	4.	$O_{2}$ , 0.28 g

12. The weight of 70 % HNO₃concentrated nitric acid solution that should be used to prepare 250 mL of 2.0 M HNO₃ is:
1. 90.0 g conc. HNO₃
2. 70.0 g conc. HNO₃
3. 54.0 g conc. HNO₃
4. 45.0 g conc. HNO₃

13. 6.02 × 10²⁰ molecules of urea are present in 100 mL of its solution. The concentration of the solution is:
1. 0.01 M
2. 0.001 M
3. 0.1 M
4. 0.02 M

14.

Mole fraction of solute in a 1.00 molal aqueous solution is:
1. 0.0177
2. 0.0344
3. 1.770
4. 0.1770

15.

25.3 g of sodium carbonate, Na₂CO₃, is dissolved in enough water to make 250 mL of a solution. If sodium carbonate completely dissociates, the molar concentrations of sodium ion, Na⁺ and carbonate ion, $C O_{3}^{2 -}$ are respectively:
(molar mass of Na₂CO₃ = 106g mol^-1)
1. 0.955 M and 1.910 M
2. 1.910 M and 0.955 M
3. 1.90 M and 1.910 M
4. 0.477 M and 0.477 M

16.

The number of atoms in 0.1 mole of a triatomic gas is (N_A= 6.02 x 10²³ mol^-1):
1. $6.026 \times 10^{22}$
2. $1.806 \times 10^{23}$
3. $3.600 \times 10^{23}$
4. $1.800 \times 10^{22}$

17.

10 g of hydrogen and 64 of oxygen were filled in a steel vessel and exploded. The amount of water produced in this reaction will be:
1. 2 mol
2. 3 mol
3. 4 mol
4. 1 mol

18.

The volume occupied by one water molecule (density = 1 g cm^-3) is:
1. $9.0 \times 10^{- 23}$    ${cm}^{3}$
2. $6.023 \times 10^{- 23}$    ${cm}^{3}$
3. $3.0 \times 10^{- 23}$    ${cm}^{3}$
4. $5.5 \times 10^{- 23}$    ${cm}^{3}$

19.

The volume of oxygen gas (O₂) needed to completely burn 1 L of propane gas (C₃H₈) (both O₂& propane measured at 0°C and 1 atm) will be:
1. 7 L
2. 6 L
3. 5 L
4. 10 L

20.

The moles of lead (II) chloride that will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl are:
1. 0.044
2. 0.333
3. 0.011
4. 0.029

21.

Concentrated aqueous sulphuric acid is 98% H₂SO₄ by mass and has a density of 1.80 g mL^-1. The volume of acid required to make one litre of 0.1 M H₂SO₄ solution is:
1. 11.10 mL
2. 16.65 mL
3. 22.20 mL
4. 5.55 mL

22. To produce 20 moles of ammonia via Haber's process, how many moles of hydrogen molecules are required?

1.	40 mol	2.	10 mol
3.	20 mol	4.	30 mol

23.

The density of a 2 M aqueous solution of NaOH is 1.28 g/ $c m^{3}$ . The molality of the solution is:
[molecular mass of NaOH = 40 $g m o l^{- 1}$ ]

1.	1.20 m	2.	1.56 m
3.	1.67 m	4.	1.32 m

24.

The maximum number of atoms is present in which of the following -

1.	1 g of Mg_(s)	2.	1 g of O₂ _(g)
3.	1 g of Li_(s)	4.	1 g of Ag_(s)

25.

Which of the following has the greatest number of molecules?
1. 64 g SO₂
2. 44 g CO₂
3. 48 g O₃
4. 8 g H₂

26.

Percentage of C, H & N of a compound is given as follows:
C=40%, H=13.33%, N=46.67%
The empirical formula of the compound will be:
1. $C H_{2} N$
2. $C_{2} H_{4} N$
3. $C H_{4} N$
4. $C H_{3} N$

27.

The mole fraction of the solute in one molal aqueous solution is:
1. 0.027
2. 0.036
3. 0.018
4. 0.009

28.

The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminum metal from bauxite by the Hall process is:
1. 90 kg
2. 540 kg
3. 180 kg
4. 270 kg
(Atomic mass : Al = 27)

29.

The number of moles of $K M n O_{4}$ reduced by one mole of KI in an alkaline medium is:
1. One
2. Two
3. Five
4. One fifth

30.

The number of significant figures in the following numbers are:

(I)	161 cm
(II)	0.0161
(III)	1.61

1. 3, 3, 3
2. 3, 4, 3
3. 3, 2, 3
4. 3, 4, 4

31.

0.33% of iron (by weight) is present in hemoglobin (Molecular wt = 67200).
The number of iron atom(s) in one molecule will be:
1. 1
2. 2
3. 3
4. 4

32.

$4 N H_{3}$ $+$ $5 O_{2}$ $\to$ $6 H_{2} O$ $+$ $4 N O$
When one mole ammonia and one mole oxygen are taken:
1. Oxygen is completely consumed
2. Ammonia is completely consumed
3. Both (1) and (2) are correct
4. None of the above options is correct

33.

The mole ratio of H₂ and O₂ gas is 8:1. The ratio of their weight will be:
1. 1 : 1
2. 2 : 1
3. 4 : 1
4. 1 : 2

34.

A compound contains C, H, and O. If C = 40% and H = 6.67% and rest is oxygen, then the empirical formula of the compound will be:
1. $C H_{2} O$
2. $C H_{4} O$
3. $C H_{4} O_{2}$
4. CHO

35.

The maximum number of molecules is present in:

1.	5L of N₂ gas at STP	2.	0.5 g of H₂ gas
3.	10g of O₂ gas	4.	15 L of H₂ gas at STP

36.

The incorrect option for mole fraction(x) is:
1. x < 1
2. – 2 ≤ x ≤ 2
3. 0 ≤ x ≤ 1
4. Always non-negative

37.

The volume of CO₂ obtained by the complete decomposition of 9.85 grams of BaCO3 is:
1. 2.24 lit.
2. 1.12 lit.
3. 0.84 lit.
4. 0.56 lit

38.

1 M, 2.5 litre NaOH solution is mixed with another 0.5 M and 3 litre NaOH solution.
The molarity of the resultant solution is:

1.	0.80 M	2.	1.0 M
3.	0.73 M	4.	0.50 M

39.

Which among the following has the maximum number of molecules?
1. 7 gm N₂
2. 2 gm H₂
3. 16 gm NO₂
4. 16 gm O₂

40.

The percentages of C, H, and N in an organic compound are 40%, 13.3%, and 46.7% respectively.
The empirical formula of the compound is:

1.	C₃H₁₃N₃	2.	CH₂N
3.	CH₄N	4.	CH₆N

41.

Find the molarity of liquid HCl if the density of liquid HCl is 1.17 g/cc.

1.	36.5	2.	18.25
3.	32.05	4.	42.10

42.

The specific volume of cylindrical virus particle is $6.02$ $\times$ $10^{- 2}$ $c c / g m w$ hose radius and length are 7 Å & 10Å respectively. If $N_{A}$ $=$ $6.023$ $\times 10^{23}$ $\text{mol}^{-1}$, find the molecular weight.
1. $ 15.4 \mathrm{~kg} / \mathrm{mol} $
2. $1.54 \times 10^4 \mathrm{~kg} / \mathrm{mol} $
3. $ 3.08 \times 10^4 \mathrm{~kg} / \mathrm{mol}$
4. $3.08 \times 10^3 \mathrm{~kg} / \mathrm{mol}$

43.

In the Haber process, 30 litres of dihydrogen and 30 litres of dinitrogen were taken for the reaction which yielded only 50% of the expected product. What will be the composition of a gaseous mixture under the above condition in the end:

1.	20 litres of ammonia, 20 litres of nitrogen, 20 litres of hydrogen
2.	10 litres of ammonia, 25 litres nitrogen, 15 litres of hydrogen
3.	20 litres of ammonia, 10 litres of nitrogen, 30 litres of hydrogen
4.	20 litres of ammonia, 25 litres of nitrogen, 15 litres of hydrogen

44.

An organic compound contains 80 % (by wt.) carbon and the remaining percentage of hydrogen. The empirical formula of this compound is:
[Atomic wt. of C is 12, H is 1]
1. CH₃
2. CH₄
3. CH
4. CH₂

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