Test 6 - Chemistry

Section A

1.

For the reaction equilibrium , $\mathrm{N}_{2} \mathrm{O}_{4}(g) \rightleftharpoons 2 \mathrm{NO}_2(g) $, the concentrations of N₂O₄ and NO₂ at equilibrium are 4.8 $\times$ 10^-2 and 1.2 $\times$ 10^-2 mol L^-1 respectively. The value of K_c for the reaction is-
1. 3.3 $\times$ 10²mol L^-1
2. 3 $\times$ 10^-1mol L^-1
3. 3 $\times$ 10^-3mol L^-1
4. 3 $\times$ 10³mol L^-1

2.

The pressure of 2 moles of an ideal gas at 546 K having volume 44.8 L is:
1. 2 atm
2. 3 atm
3. 4 atm
4. 1 atm

3.

The equilibrium constant for the reaction
$\mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)$
at temperature T is $4 \times 10^{-4}$ . The value of K_c for the reaction,
$\mathrm{NO}(g) \rightleftharpoons \frac{1}{2} \mathrm{~N}_{2}(g)+\frac{1}{2} \mathrm{O}_{2}(g)$at the same temperature) is :

1. $2.5 \times 10^{2}$
2. $5 \times 10^{1}$
3. $4 \times 10^{-4}$
4. $2 \times 10^{-2}$

4.

pK_a of a weak acid (HA) and pK_b of a weak base (BOH) are 3.2 and 3.4, respectively. The pH of their salt (AB) solution is:
1. 7.0
2. 1.0
3. 7.2
4. 6.9

5.

Entropy decreases during:
1. crystallization of sucrose from solution
2. rusting of iron
3. melting of ice
4. vaporization of camphor

6.

Arrange the following solution in the decreasing order of pOH :
(A). 0.01 M HCl
(B). 0.01 M NaOH
(C). 0.01 M ${CH}_{3} COONa$
(D). 0.01 M NaCl
1. (B) > (C) > (D) > (A)
2. (A) > (C) > (D) > (B)
3. (B) > (D) > (C) > (A)
4. (A) > (D) > (C) > (B)

7. $\Delta G^o $ for a reversible reaction having equilibrium constant 10^–2 at 27°C will be:
1. 500R
2. 2.303 × 600R
3. 600R
4. 2.303 × 500R

8.

Consider the following statements

a.	The correct order of increasing acidic strength is CH₄ < NH₃< HF < H₂O
b.	Ionic product of water is temperature dependent.
c.	A monobasic acid with K_a = 10^–5has pH = 5. The degree of dissociation of this acid is 50 %.

The correct statements are:
1. (a), and (b)
2. (a), (b), and (c)
3. (a), and (C)
4. (b), and (c)

9.

The enthalpy and entropy change for a chemical reaction are
–2.5 × 10³ cal and 7.4 cal deg^–1 respectively. Predict the reaction at 298 K is
1. Spontaneous
2. Reversible
3. Irreversible
4. Non-spontaneous

10. 5 L of a gas is heated from 27°C to 227°C at constant pressure, then final volume of the gas will be:
1. 42.04 L
2. 10 L
3. 8.33 L
4. 14.38 L

11.

The enthalpy of vaporisation of a liquid is 30 kJ mol^–1 and entropy of vaporisation is 75 J mol^–1 k^–1. The boiling point of the liquid at 1 atm is:
1. 50 K
2. 400 K
3. 450 K
4. 600 K

12. If bond enthalpies of $C-C,C-H,O=O,C=O $ and $O-H $ are
a, b, c, d, and e respectively, then the heat of combustion of ethane will be:
1. $6 b+\frac{7}{2} c+a-2 d-3e $
2. $b+c+a-4 d-3e $
3. $6 b+\frac{7}{2} c+a-4 d-6e $
4. $6 b+7 c+a-4 d-6e $

13.

Five moles of an ideal gas at 1 bar and 298 K are expanded into a vacuum till the volume doubles. The work done is:
1. –RT ln V₂/V₁
2. C_V(T₂ – T₁)
3. zero
4. – RT(V₂ – V₁)

14.

600 cc of a gas at a pressure of 750 mm is compressed to 500 cc. Taking the temperature to remain constant, the increase in pressure is:
1. 150 mm
2. 250 mm
3. 350 mm
4. 450 mm

15.

According to the law, a perfect crystal's entropy is 0 at absolute zero, which is:
1. The first law
2. Second law
3. Third law
4. None of the above

16.

Consider the van der Waals constants, a and b, for the following gases.
Gas Ar Ne Kr Xe
a/(atm dm⁶ mol^–2) 1.3 0.2 5.1 4.1
b/(10^–2dm³ mol^–1) 3.2 1.7 1.0 5.0
Which gas is expected to have the highest critical temperature?
1. Xe
2. Ne
3. Kr
4. Ar

17.

The entropy change for the melting of 'x' moles of ice at 273 K and 1 atm pressure is 28.80 cal K^-1.
(Given: heat of fusion is 80 cal g^-1)
The value of 'x' is:
1. 4.32 mol
2. 8.56 mol
3. 10.36 mol
4. 5.46 mol

18. The equilibrium constants for a hypothetical reaction $A_2~\rightleftharpoons~B_{2} $ at 500 K and 700 K are 1×10^-10 and 1×10^-5 respectively.
The reaction is:
1. endothermic
2. exothermic
3. fast
4. slow

19.

Match List-I (compounds) with List-II (Oxidation states of nitrogen) and select an answer using the codes given below the lists.

List - I		List - II
(a)	NaN₃	(i)	+5
(b)	N₂H₂	(ii)	+2
(c)	NO	(iii)	-1/3
(d)	N₂O₅	(iv)	-1

Options:	(a)	(b)	(c)	(d)
1.	iii	iv	ii	i
2.	iv	iii	ii	i
3.	iii	iv	i	ii
4.	iv	iii	i	ii

20.

If the equilibrium constant for $A ⇌ B + C is K_{eq}^{(1)}$ and that of $B + C ⇌ P is K_{eq}^{(2)}$ , the equilibrium constant for $A ⇋ P$ is:
1. $K_{eq}^{(2)} - K_{eq}^{(1)}$
2. $K_{eq}^{(1)} \times K_{eq}^{(2)}$
3. $K_{eq}^{(1)} + K_{eq}^{(2)}$
4. $K_{eq}^{(2)} / K_{eq}^{(1)}$

21. The number of moles of $K_2Cr_2O_7$ required to oxidise one mole of $FeSO_4$ in acidic medium is:
1. 6
2.  $1 \over 2$
3.  $1 \over 3$
4.  $1 \over 6$

22. 2 moles of $NOCl $ taken in 1 L of closed container and it dissociates into NO and Cl₂ gas. The reaction is as follows:
$2NOCl\rightleftharpoons 2NO+Cl_2 $
At equilibrium, if 0.4 moles of NO are obtained, then the value of $K_c $ is:

1.	142 × 10^-4	2.	142 × 10^-6
3.	125 × 10^-4	4.	130 × 10⁴

23.

The mixture that will produce a buffer solution when mixed in equal volumes is:

1.	0.1 mol dm^-3 NH₄OH and 0.1 mol dm^-3 HCl
2.	0.05 mol dm^-3 NH₄OH and 0.1 mol dm^-3 HCl
3.	0.1 mol dm^-3 NH₄OH and 0.05 mol dm^-3 HCl
4.	0.1 mol dm^-3 CH₃COONa and 0.1 mol dm^-3 NaOH

24.

Assertion (A):	Sparingly soluble salts AB and XY₂ with the same solubility product, will have different solubility.
Reason (R):	Solubility of sparingly soluble salt depend upon solubility product as well as the type of salt.

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

25.

Which one of the following 0.01 M aqueous solutions has a pH > 7.0?
1. ${AlBr}_{3}$
2. $NaI$
3. ${NH}_{4} Cl$
4. ${Na}_{2} {CO}_{3}$

26.

A cell contains two hydrogen electrodes. Anode is in contact with a solution of 10^-4 M H⁺ ions. E.M.F. of the cell is 0.118 V at $25 ° C$ . pH of solution at cathode will be:
1. 1
2. 2
3. 0
4. –1

27.

Assertion (A):	The observed molar mass of acetic acid in benzene is more than the normal molar mass of acetic acid.
Reason (R):	Molecules of acetic acid dimerise in benzene due to hydrogen bonding.

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

28. What is the concentration of a glucose solution in intravenous injection in gram/lit which is isotonic with blood solution which has osmotic pressure 7.93 bar at 300 K ?
1. 62 g
2. 0.58 g
3. 0.62 g
4. 58 g

29.

The potential of the cell containing two hydrogen electrodes as given below is-
Pt; $\frac{1}{2}$H_₂(g)|H^⁺(10^-8M)|H^⁺(0.001 M)| $\frac{1}{2}$H_₂(g)Pt
1. – 0.295 V
2. – 0.0591 V
3. 0.295 V
4. 0.0591 V

30. If mass percentage (w/w) of ethanol in water is 25% then the molality of the solution will be:
1. 3.2 m
2. 4.5 m
3. 5.9 m
4. 7.2 m

31.

Frenkel defect is also known as-
(a) Stoichiometric defect
(b) Dislocation defect
(c) Impurity defect
(d) Non-stoichiometric defect
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

32. Which among the following represents a concentration cell?

1.	$I^-(aq) \|I_2(s) \|\| Br_2(l) \|Br^-(aq) $
2.	$Zn(s) \| Zn^{2+} (aq) \|\| Pb^{2+} (aq) \| Pb(s) $
3.	$Pt,H_2(g) \|H_2O(l) \| OH^-(aq) \|\|O_2(g) \|OH^- (aq), Pt$
4.	$Ag(s) \| Ag^+ (aq) \|\| Ag^+ (aq) \|Ag(s) $

33. Which condition is not satisfied by an ideal solution?
1. $\Delta$_mix V = 0
2. $\Delta$_mix S = 0
3. Obeyance to Roult's Law
4. $\Delta$_mix H = 0

34.

Copper crystallises in a face-centred cubic lattice with a unit cell length of 361 pm. What
is the radius of copper atom in pm?
1. 128
2. 157
3. 181
4. 108

35. Following limiting molar conductivities are given as
$\lambda_m^o(CaCl_2)=x~S~\text{cm}^2\text{mol}^{-1},$ $\lambda^o(MgSO_4)=y~S~\text{cm}^2\text{mol}^{-1}$ and $\lambda^o(CaSO_4)=z~S~\text{cm}^2\text{mol}^{-1}.$
The $\lambda^o(MgCl_2)$ in $S~\text{cm}^2~\text{mol}^{-1}$ will be:
1. $2x+y-z$
2. $x-\frac{y}{2}-\frac z2$
3. $x+y-z$
4. $x-\frac y2-z$

Section B

36.

Statement I:	The unit of molar conductivity is S cm² mol.
Statement II:	Galvanic cells that are designed to convert the energy of combustion of fuels like hydrogen, methane, methanol, etc. directly into electrical energy are called fuel cells.

1.	Statement I is correct but statement II is incorrect.
2.	Statement I is incorrect but statement II is correct.
3.	Statement I and statement II both are correct.
4.	Statement I and statement II both are incorrect.

37.

Assertion (A):	The standard reduction potentials of three metallic ions A, B, and C are –0.3, –0.5, and 0.8 volts respectively. Therefore, the oxidizing power of ions is C > A > B.
Reason (R):	The higher the standard reduction potential, the higher the oxidizing power.

1.	Both (A) and (R) are True and (R) is the correct explanation of (A).
2.	Both (A) and (R) are True but (R) is not the correct explanation of (A).
3.	(A) is True but (R) is False.
4.	(A) is False but (R) is True.

38. On the basis of magnetic property, magnetite is classified as-:
1. Ferromagnetism
2. Ferrimagnetism
3. Antiferromagnetism
4. Diamagnetism

39. To avoid bends, as well as, the toxic effects of high concentrations of nitrogen, the air in the scuba tank is diluted with:
1. CO₂
2. NO
3. He
4. Ne

40.

Which of the following statements is not correct?

1.	The fraction of the total volume occupied by the atoms in a primitive cell is 0.48.
2.	Molecular solids are generally volatile.
3.	The number of carbon atoms in an unit cell of diamond is 8.
4.	The number of Bravais lattices in which a crystal can be categorized is 14.

41. The vapour pressure of an aqueous solution obtained after mixing 900 g H₂O with 120 g urea at 373.15 K will be:
1. 650 mmHg
2. 760 mmHg
3. 730.77 mmHg
4. 855 mmHg

42. For a conductivity cell containing 10^–3M KCl solution at 298 K, the resistance is 1500 ohm and the conductivity is 0.15×10^–3 S cm^–1. The cell constant of the cell is:
1. 10.0 cm^–1
2. 0.10 cm^–1
3. 0.115 cm^–1
4. 0.225 cm^–1

43. An example of a positively charged sol is:
1. Haemoglobin(blood)
2. Acid dye eosin
3. CdS
4. Golden sol

44. The value of k at T→ ∞ in the Arrhenius equation would be:

1.	$A $	2.	$-\mathrm{A} $
3.	$\mathrm{e}^A $	4.	$\mathrm{e}^{-A}$

45. Given the reaction, $A + B \rightarrow Products,$ , when concentration of A is fixed and concentration of B is increased 3 times then rate of reaction increases 27 times. Now, when the concentration of A and B both are doubled, then the rate of reaction increases 8 times. The rate law for the reaction will be
1. $Rate = K [A]^2[B] $
2. $Rate = K [B]^3 $
3. $Rate = K [A]^3[B] $
4. $Rate = K [A]^3[B]^2$

46.

Statement I:	For complex reactions, order has no meaning.
Statement II:	Order of a reaction is experimental quantity.

1. Statement-I is incorrect but statement-II is correct
2. Both statement-I and statement-II are correct
3. Both statement-I and statement-II are incorrect
4. Statement-I is correct but statement-II is incorrect

47.

The correct statements regarding the situation, when a Lyophilic sol is added to a Lyophobic sol, are-
a. Lyophobic sol is protected
b. Lyophilic sol is protected
c. Film of lyophilic sol is formed over lyophobic sol
d. Film of lyophobic sol is formed over lyophilic sol
1. (a, b)
2. (b, c)
3. (c, a)
4. (a, d)

48. Out of the given equations, which can be used to explain the temperature dependence of the rate of a chemical reaction?
1. $T \ln (\mathrm{k} / \mathrm{A})= \mathrm{-E}_{\mathrm{a}} \cdot \mathrm{R} $
2. $ R T \ln \left(\frac{k}{A}\right)=-E_a $
3. $ R \ln (k / A)=-E_a \cdot T $
4. $E_a \ln (\mathrm{k} / \mathrm{A})=-\mathrm{R} \cdot \mathrm{T} $

49. For a first-order reaction, the relationship between the time required for 99% completion of the reaction $(t_{0.99}) $ and the time required for completion of 90% of the reaction $(t_{0.90}) $ is:
1. $t_{0.90} = 10 t_{0.99}$
2. $t_{0.90} = 2 t_{0.99} $
3. $t_{0.99} = 10 t_{0.90} $
4. $t_{0.99} = 2 t_{0.90} $

50.

Which of the following rate laws has an over all order of 0.5 for the reaction A + B + C $\to$ product ?
1. R=k[A].[B].[C]
2. R=k[A]^0.5[B]^0.5[C]^0.5
3. R=k[A]^1.5[B]^-1[C]⁰
4. R=k[A][B]⁰[C]^0.5

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1.	\(I^-(aq) \|I_2(s) \|\| Br_2(l) \|Br^-(aq) \)
2.	\(Zn(s) \| Zn^{2+} (aq) \|\| Pb^{2+} (aq) \| Pb(s) \)
3.	\(Pt,H_2(g) \|H_2O(l) \| OH^-(aq) \|\|O_2(g) \|OH^- (aq), Pt\)
4.	\(Ag(s) \| Ag^+ (aq) \|\| Ag^+ (aq) \|Ag(s) \)

1.	\(A \)	2.	\(-\mathrm{A} \)
3.	\(\mathrm{e}^A \)	4.	\(\mathrm{e}^{-A}\)

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