Enthalpy of Solution

Q.

What is meant by exothermic and endothermic reactions? Give examples.

Q.

Calculate the solubility of hydrogen in water at 25 degree Celsius if its partial pressure above the solution is 1 bar. Given that Henry's constant for hydrogen at 25 degree Celsius is 71.18 K bar.

Q. The percentage composition of Mohr's salt is as follows. Fe²+=14.32% NH4=9.20% SO4²‐=49% REST being water of crystallization.Find the empirical formula of Mohr's salt.

Q.

Which of the following aqueous solution has maximum freezing point

.01 M nacl

.05 M c2h5oh

.005 M mgi2

.01 M mgso4

Q. Depression of freezing point of 0.01 molal aqueous CH3COOH Solution is 0.204^°C. 1 molal urea freezes at -1.86^°C. Assuming molarity equal to molality, pH of CH3COOH solution is

Q. The average $S-F$ bond energy in $kJmo{l}^{-1}$ of $S{F}_6$ is _____.(Rounded off to the nearest integer

[Given : The values of standard enthalpy of formation of $S{F}_6\left(g\right),S\left(g\right)andF\left(g\right)$ are - 1100, 275 and 80 kJ $mo{l}^{-1}$ respectively]

Q. 1*10^-3 m solution of Pt(NH3)4Cl4 in water shows depression in freezing point by 0.0054 C. The given structure of the following compound will be (Given Kf=1.85 K/m) (1) [Pt(NH3)4]Cl4 (2) [Pt(NH3)3Cl]Cl3 (3) [Pt(NH3)Cl2]Cl2 (4) [Pt(NH3)Cl3]Cl.

Q.

Highest melting point would be of

$1.AlC{l}_3$

$2.LiCl$

$3.NaCl$

$4.BeC{l}_2$

Explain how

Q. The degree of dissociation of Calcium nitrate in dilute aqueous solution contain 7g of salt per 100g of water at 100°C is 70% . If vapour pressure of water at 100°C is 760mm of Hg . Calculate the vapour pressure of the solution .

Q. 57. calculate bp of solution cntaining 25g urea & 25g thio urea in 500g of chloroform boiling point of pure chloroform is 61.2 degree celsius & Kb = 3.63

Q. 7. How to attempt this type of ques.- Q.which of the following aqueous solutions has highest freezing point- a) 0.1 M NaCl b)0.1M BaCl2 c) 0.1M Al2(SO4)3 d)0.1M urea

Q. A solution of A and B with 30% mole of A in solution is in equilibrium with its vapour which contains 60% mole of A. What will be the ratio of the vapour pressure of pure A to that of pure B?

Q. What will be the standard enthalpy change for the reaction $O{F}_2\left(g\right)+H_{2}O\left(g\right)\to O_2\left(g\right)+2HF\left(g\right)$ at 298K if enthalpies
of formation of $O{F}_2\left(g\right),H_{2}O\left(g\right)$ and $HF\left(g\right)$ are +20, -250 and -270kJ $mo{l}^{-1}$ respectively.

1. + 310 kJ
2. -310 kJ
3. + 770 kJ
4. - 770 kJ

Q. G (Gibbs free energy) for every solution is said to be less than 0. but isnt it false to say that as in the non ideal solution with positive deviation the gibbs free energy should increase? and S (entropy) of a solution is also always greater than 0?

Q. One mole of soda ash dissolves in water with evolution of 25 kJ of heat. Dissolution of 1 mol of the hydrate crystals in water resulted in the absorption of 67 kJ of heat. The heat released due to hydration of soda ash is

1. - 92 kJ
2. + 42 kJ
3. - 42 kJ
4. -102 kJ

Q. The freezing point of aqueous solution containing20% w/w urea and 20% w/w NaOH also, will be(if K, of H2O is 1.8 K kg mol-)

Q. 89.The degree of inonization of HF in 0.100 m aqueous solution is [ freezing point of the solution = -0.197C and Kf for water = 1.86C]

Q. The standard change in Gibbs energy for the reaction: $H_{2}O\rightleftharpoons H^{+}+O{H}^{-}$ at ${25}^{\circ }C$

1. $-100kJ$
2. $100kJ$
3. $90kJ$
4. $-90kJ$

Q.

Calculate weight of hydrogen gas present when 85 gm of Ammonia is heated

Q.

Assertion: Cooling is caused when a liquid evaporates.
Reason: Evaporating liquid particles absorb energy from the surroundings.

1. Both assertion and reason are correct and reason is correct explanation for assertion.

2. Both assertion and reason are correct but reason is not correct explanation for assertion.

3. Assertion is correct but reason is incorrect.

4. Assertion is incorrect but reason is correct.

Q.

Which of the two has lower freezing point, 2m NaCl or 5m NaCl aqueous solution?

1. 2m NaCl solution

2. Both have same freezing point

3. 5m NaCl solution

4. The solutions cannot freeze

Q. What is the density of hydrogen gas at S.T.P.

Q. depression in freezing point of 0.01 molal aq CH3COOH soln is 0.0204 C . 1 molal urea soln freezes at -1.86 C . assuming molality =MOLARITY , pH of CH3COOH sol is 2 3 3.2 4.2

Q. Which of the following aqueous solutions has the highest freezing point 0.6m fructose 0.3m CaCl2 0.1m Al2(SO4)3 0.2m Mg3(PO4)2

Q.

0.01 M solutions of urea, common salt and sodium sulphate are taken The ratio of depression of freezing point will be in the ratio

1. 2:2:3

2. 1:2:3

3. 1:2:1

4. 1:1:1

Q.

Write true or false. Correct the false statement.

If heat is evolved during the reaction, it is endothermic.

1. True
2. False

Q. what is change in internal energy, entropy, enthalpy, gibbs free energy for an ideal solution?

Q. 13 liquids A and B form an ideal solution . if Xa and Ya are the mole fractions of A in the solution and in vapour phase in equilibrium, then(Given Pa^° >Pb^° -) a)Ya/Xa=1 b)Ya/Xa>1 c)Ya/Xa<1 d)Ya+Xa=1

Q.

Molar conductivity for a compound AB is 145.0 Scm²mol^-1 and for CB is 110.1 Scm²mol^-1. Limiting molar conductivity for A⁺ is 73.5 Scm²mol^-1. What is limiting molar conductivity for C⁺?

1. 38.6 S cm² mol^-1

2. 90.8 S cm² mol^-1

3. 326.6 S cm² mol^-1

4. 181.6 S cm² mol^-1

Q. 7. MX2 dissociates into M2+ and X ions in an aqueous solution, with a degree of dissociation (a) of 0.5. The ratio of the observed depression of freezing point of the aqueous solution to the value of the depression of freezing point in the absence of ionic dissociation is