Concentration Terms

Q. The ratio of moles of $N{a}_{2}C{O}_3$ to total number of moles in a 100 mL aqueous solution of $N{a}_{2}C{O}_3$ is 1:5. If 90 g of water is present in 100 mL of solution, find the molarity of the solution.

1. 1.2580 M
2. 0.0125 M
3. 0.1538 M
4. 12.5 M

Q. 100 mL of a 0.1 M NaCl solution is added to 300 mL of a 0.2 M $MgC{l}_2$ solution. 100 mL of this solution was further diluted with 400 mL of water. The molarity of $C{l}^{-}$ ions in the resultant solution is:

1. 0.725 M
2. 0.055 M
3. 0.045 M
4. 0.065 M

Q.

How to determine the Vant Hoff factor of a substance from its formula?

Q. In a buffer solution consisting of a weak acid and its salt, the ratio of concentration of salt to acid is increased tenfold, then the $pH$ of the solution will:

1. Increase by one
2. Increase tenfold
3. Decrease by one
4. Decrease tenfold

Q.

The molal depression constant for water is 1.86Kkg/mol. If 0.5 mole of sucrose is dissolved in 500g of water the freezing point is depressed by

1. 1.86

2. 0.186

3. 0.93

4. 0.093

Q.

An aqueous solution of glucose was prepared by dissolving 18g in 90g of water. The relative lowering of vapour pressure is

1. 0.2

2. 0.02

3. 20

4. 196

Q.

The molarity of 0.006 mole of NaCl in 100ml solution is:

1. 0.6
2. 0.06
3. 0.006
4. 0.066

Q. Molarity of $H_{2}S{O}_4$ is 18M. Its density is 1.8 g/ml. Hence molality is

1. 36
2. 200
3. 500
4. 18

Q. One litre of 1 molar $H_{2}S{O}_4$ solution has been diluted by 5 litre water, the normality of the solution is

1. 0.2N
2. 5N
3. 10N
4. 0.33N

Q. A solution of $\left(A{l}_2\right(S{O}_4{)}_3)$ contain 22% salt by weight and density of solution is 1.253 g/mL. The molarity, normality and molality of the solution are:

1. 0.806 M, 4.83 N, 0.825 m
2. 0.825 M, 48.3 N, 0.805 m
3. 4.83 M, 4.83 N, 4.83 m
4. None

Q. In which of the following condition, a mixture has the ability to act as an acidic buffer?

1. $\frac{\left[C{H}_{3}CO{O}^{-}\right]}{\left[C{H}_{3}COOH\right]}>10$
2. None of the above
3. $\frac{\left[C{H}_{3}CO{O}^{-}\right]}{\left[C{H}_{3}COOH\right]}<0.1$
4. $0.1<\frac{\left[C{H}_{3}CO{O}^{-}\right]}{\left[C{H}_{3}COOH\right]}<10$

Q.

9.8g of H₂SO₄ is present in 2 litres of a solution. The molarity of the solution is:

1. 0.1 M

2. 0.05 M

3. 0.2 M

4. 0.01 M

Q. Which of the following represents a correct relation for a basic buffer formed by $N{H}_{4}OH$ and $N{H}_{4}Cl$ ?

1. $pOH=p{K}_b+log\left[\frac{\left[N{H}_4^{+}\right]}{\left[N{H}_{4}OH\right]}\right]$
   
2. $pH=p{K}_b+log\left[\frac{\left[N{H}_4^{+}\right]}{\left[N{H}_{4}OH\right]}\right]$
   
   
3. $pOH=p{K}_b+log\left[\frac{\left[N{H}_{4}OH\right]}{\left[N{H}_4^{+}\right]}\right]$
   
4. $pH=p{K}_a+log\left[\frac{\left[N{H}_{4}OH\right]}{\left[N{H}_4^{+}\right]}\right]$

Q. The density of $3M$ solution of sodium thiosulphate $\left(N{a}_2{S}_2{O}_3\right)$ is $1.25$ g/mL.
Which of the following option(s) is/are correct?

Q.

Copper matte is a molten mixture of

1. Cu₂S + little FeS

2. Cu₂S + little FeO

3. Cu₂O + little FeO

4. Cu₂O + little FeS

Q.

In a certain solvent phenol dimerises to the extent of 60%. Its observed molecular mass in the solvent would be (M.M Phenol = 94)

1. Less than 94

2. 94

3. Greater than 94

4. Nothing can be said

Q.

25 ml of 3.0 M HNO₃ are mixed with 75 ml of 4.0 M HNO₃. If the volumes are additive, the molarity of the final mixture would be:

1. 3.25 M

2. 4.0 M

3. 3.75 M

4. 3.50 M

Q. The percentage composition in a sample of $CaC{O}_3$ is given as: $Ca=40\%;C=12\%;O=48\%$. What will be the weight of $Ca$ in $4\text{g}$ of a sample of $CaC{O}_3$ obtained from another source, if the law of constant proportions is true?

1. $0.16\text{g}$
2. $16\text{g}$
3. $1.6\text{g}$
4. $0.016\text{g}$

Q.

The number of molecules in 4.25 g of ammonia is approximately

1. 0.5 X 10²³

2. 1.5 X 10²³

3. 3.5 X 10²³

4. 2.5 X 10²³

Q. Calculate molality of 2.5 g of ethanoic acid $\left[C{H}_{3}COOH\right]$ in 75 g of benzene.

1. $0.551molk{g}^{-1}$
   
2. $0.556molk{g}^{-1}$
   
3. $0.558molk{g}^{-1}$
   
4. $0.552molk{g}^{-1}$

Q. Calculate molality of 2.5 g of ethanoic acid $\left[C{H}_{3}COOH\right]$ in 75 g of benzene.

1. $0.551molk{g}^{-1}$
   
2. $0.556molk{g}^{-1}$
   
3. $0.558molk{g}^{-1}$
   
4. $0.552molk{g}^{-1}$

Q.

The normality of 0.3 M phosphorus acid (H₃PO₃) is:

1. 0.1

2. 0.9

3. 0.3

4. 0.6

Q.

Molarity is expressed as

1. Gram/litre

2. Moles/litre

3. Litre/mole

4. Moles/1000 gms

Q. Assertion (A): Molality of solution does not change with change in temperature.
Reason (R): Molality is defined as no. of moles of solute per kg of solvent. Which of the following is correct?

1. Both A and R are true and R is correct explanation of A
2. Both A and R are true and R is not a correct explanation of A
3. A is true but R is false.
4. A is false but R is true.

Q.

If the observed and the theoretical molecular mass of NaCl is found to be 31.80 and 58.50, then the percentage dissociation of NaCl is

1. 83.96

2. 8.39

3. 90

4. 100

Q.

Shikhar was to perform a neutralization reaction in laboratory. In order to neutralize 500 ml of $2MNaOH$ solution he was supposed to add certain volume of $1M{H}_{3}P{O}_3$ solution, but by mistake, he added the same volume of water instead. What is the molality of the resulting solution – Assume density of the original solution = $1.08g/cc$ Density of water = 1 g/cc.

1. 0.67

2. 1

3. 1.2

4. 2

Q.

What will be the molarity of a solution containing 5 g of sodium hydroxide in 250 ml solution:

1. 0.5

2. 1.0

3. 2.0

4. 0.1

Q.

If 1 L 1 M solution of sulphuric acid is diluted by 5 L of water, what will be the final normality of the solution?

1. 0.2 N

2. 5 N

3. 10 N

4. 0.33 N

Q. Calculate the vapour pressure of an aqueous solution of $1.0$ molal glucose solution at ${100}^{o}C.$

1. $13.68\text{mm Hg}$
2. $136.8\text{mm Hg}$
3. $760\text{mm Hg}$
4. $746.32\text{mm Hg}$

Q. One litre of 1 molar $H_{2}S{O}_4$ solution has been diluted by 5 litre water, the normality of the solution is

1. 0.2N
2. 5N
3. 10N
4. 0.33N