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2022 15 questions

Q632022 · 29 Jul 2022 · Shift 1
The first ionization enthalpy of Na, Mg and Si, respectively, are : 496, 737 and $786 kJ mo l^{- 1}$ . The first ionization enthalpy ( $kJ mo l^{- 1}$ ) of Al is :
1. A.487
2. B.768
3. C.577
4. D.856
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Answer: C
Q832022 · 29 Jul 2022 · Shift 1· Numerical answer
When $600 mL$ of $0.2 M HN O_{3}$ is mixed with $400 mL$ of $0.1 M NaOH$ solution in a flask, the rise in temperature of the flask is ________ $\times 1 0^{- 2}^{\circ} C$ . (Enthalpy of neutralisation $= 57 kJ mo l^{- 1}$ and Specific heat of water $= 4.2 J K^{- 1} g^{- 1}$ ) (Neglect heat capacity of flask)
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Answer: 54
Q662022 · 29 Jul 2022 · Shift 2
Which of the following 3d-metal ion will give the lowest enthalpy of hydration ( $Δ_{hyd} H$ ) when dissolved in water ?
1. A. $C r^{2 +}$
2. B. $M n^{2 +}$
3. C. $F e^{2 +}$
4. D. $C o^{2 +}$
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Answer: B
Q622022 · 28 Jul 2022 · Shift 2
Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ . Assertion A : The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state. Reason $R$ : The value of $Δ G^{⊖}$ becomes more on negative side as entropy is higher in liquid state than solid state. In the light of the above statements, choose the most appropriate answer from the options given below
1. A.Both A and R are correct and R is the correct explanation of A
2. B.Both A and R are correct but R is NOT the correct explanation of A
3. C.A is correct but R is not correct
4. D.A is not correct but R is correct
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Answer: A
Q762022 · 27 Jul 2022 · Shift 2
An element A of group 1 shows similarity to an element B belonging to group 2. If A has maximum hydration enthalpy in group 1 then B is :
1. A.Mg
2. B.Be
3. C.Ca
4. D.Sr
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Answer: A
Q822022 · 27 Jul 2022 · Shift 2· Numerical answer
A gas (Molar mass $= 280 g mo l^{- 1}$ ) was burnt in excess $O_{2}$ in a constant volume calorimeter and during combustion the temperature of calorimeter increased from $298.0 K$ to $298.45 K$ . If the heat capacity of calorimeter is $2.5 kJ K^{- 1}$ and enthalpy of combustion of gas is $9 kJ mo l^{- 1}$ then amount of gas burnt is ____ $g$ . (Nearest Integer)
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Answer: 35
Q832022 · 26 Jul 2022 · Shift 1· Numerical answer
$2.4 g$ coal is burnt in a bomb calorimeter in excess of oxygen at $298 K$ and $1 atm$ pressure. The temperature of the calorimeter rises from $298 K$ to $300 K$ . The enthalpy change during the combustion of coal is $- x kJ mo l^{- 1}$ . The value of $x$ is ____. (Nearest Integer) (Given : Heat capacity of bomb calorimeter $20.0 kJ K^{- 1}$ . Assume coal to be pure carbon)
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Answer: 200
Q742022 · 25 Jul 2022 · Shift 2
For micelle formation, which of the following statements are correct? A. Micelle formation is an exothermic process. B. Micelle formation is an endothermic process. C. The entropy change is positive. D. The entropy change is negative.
1. A.A and D only
2. B.A and C only
3. C.B and C only
4. D.B and D only
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Answer: C
Q832022 · 25 Jul 2022 · Shift 2· Numerical answer
While performing a thermodynamics experiment, a student made the following observations. $HCl + NaOH \to NaCl + H_{2} O ΔH = - 57.3 kJ mo l^{- 1}$ $C H_{3} COOH + NaOH \to C H_{3} COONa + H_{2} O ΔH = - 55.3 kJ mo l^{- 1}$ The enthalpy of ionization of $C H_{3} COOH$ as calculated by the student is ___________ $kJ mo l^{- 1}$ . (nearest integer)
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Answer: 2
Q652022 · 30 Jun 2022 · Shift 1
The correct order of electron gain enthalpy ( $- ve$ value) is :
1. A. $O > S > S e > T e$
2. B. $O < S < S e < T e$
3. C. $O < S > S e > T e$
4. D. $O < S > S e < T e$
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Answer: C
Q632022 · 27 Jun 2022 · Shift 1
Match List-I with List-II. $(A) (B) (C) (D) List - I Spontaneous process Process with Δ P = 0, Δ T = 0 Δ H_{r e a c t i o n} Exothermic Process (I) (II) (III) (IV) List - II Δ H < 0 Δ G_{T, P} < 0 Isothermal and isobaric process [Bond energies of molecules in reactants] - [Bond energies of product molecules]$ Choose the correct answer from the options given below :
1. A.(A) - (III), (B) - (II), (C) - (IV), (D) - (I)
2. B.(A) - (II), (B) - (III), (C) - (IV), (D) - (I)
3. C.(A) - (II), (B) - (III), (C) - (I), (D) - (IV)
4. D.(A) - (II), (B) - (I), (C) - (III), (D) - (IV)
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Answer: B
Q812022 · 26 Jun 2022 · Shift 1· Numerical answer
For complete combustion of methanol $C H_{3} OH (l) + \frac{3}{2} O_{2} (g) \to C O_{2} (g) + 2 H_{2} O (l)$ the amount of heat produced as measured by bomb calorimeter is $726 kJ mol^{- 1}$ at $2 7^{\circ} C$ . The enthalpy of combustion for the reaction is $- x kJ mol^{- 1}$ , where x is ________. (Nearest integer) (Given : $R = 8.3 JK^{- 1} mol^{- 1}$ )
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Answer: 727
Q862022 · 26 Jun 2022 · Shift 2· Numerical answer
$Cu (s) + S n^{2 +} (0.001 M) \to C u^{2 +} (0.01 M) + Sn (s)$ The Gibbs free energy change for the above reaction at $298 K$ is $x \times 1 0^{- 1} kJ mo l^{- 1}$ . The value of $x$ is ____. [nearest integer] [Given : $E_{C u^{2 +} /Cu}^{⊖} = 0.34 V$ ; $E_{S n^{2 +} /Sn}^{⊖} = - 0.14 V$ ; $F = 96500 C mo l^{- 1}$ ]
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Answer: 983
Q832022 · 25 Jun 2022 · Shift 1· Numerical answer
The standard entropy change for the reaction $4 Fe (s) + 3 O_{2} (g) \to 2 Fe_{2} O_{3} (s)$ is $- 550 J K^{- 1}$ at $298 K$ . [Given : The standard enthalpy change for the reaction is $- 165 kJ mol^{- 1}$ ]. The temperature in $K$ at which the reaction attains equilibrium is . (Nearest Integer)
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Answer: 300
Q642022 · 24 Jun 2022 · Shift 2
At $2 5^{\circ} C$ and $1 atm$ pressure, the enthalpies of combustion are as given below : | Substance | $H_{2}$ | $C (graphite)$ | $C_{2} H_{6} (g)$ | | :--- | :--- | :--- | :--- | | $\frac{Δ _{c} H ^{⊖}}{kJ mol ^{- 1}}$ | $- 286.0$ | $- 394.0$ | $- 1560.0$ | The enthalpy of formation of ethane is
1. A. $+ 54.0 kJ mol^{- 1}$
2. B. $- 68.0 kJ mol^{- 1}$
3. C. $- 86.0 kJ mol^{- 1}$
4. D. $+ 97.0 kJ mol^{- 1}$
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Answer: C