11th Standard Syllabus & Materials
11th Standard
Tamilnadu 11th Standard Tamil மொழி கலை -செய்யுள் - ஒவ்வொரு புல்லையும் Important Questions And Answers Study Material - QB365
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Tamilnadu 11th Standard Tamil பீடு பெற நில் - இலக்கணம் - பகுபத உறுப்புகள் Important Questions And Answers Study Material - QB365
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Tamilnadu 11th Standard Tamil பீடு பெற நில் - செய்யுள் - குறுந்தொகை Important Questions And Answers Study Material - QB365 Set B
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Tamilnadu 11th Standard Tamil பீடு பெற நில் - செய்யுள் - குறுந்தொகை Important Questions And Answers Study Material - QB365 Set A
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Tamilnadu 11th Standard Tamil பீடு பெற நில் - செய்யுள் - காவடிச்சிந்து Important Questions And Answers Study Material - QB365 Set B

Published on: 13/05/2022
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Questions + Answers key
Take MCQ Chemistry Test1.
The partial pressure of carbon dioxide in the reaction
CaCO3 (s) ⇌ CaO (s) + CO2(g) is 1.017 × 10–3 atm at 5000C. Calculate Kp at 6000C for the reaction. ΔH for the reaction is 181 KJ mol–1 and does not change in the given range of temperature.
2.
1 mol of CH4, 1 mole of CS2 and 2 mol of H2S are 2 mol of H2 are mixed in a 500 ml flask. The equilibrium constant for the reaction KC = 4 x 10–2 mol2 lit–2. In which direction will the reaction proceed to reach equilibrium ?
3.
1 mol of PCl5, kept in a closed container of volume 1 dm3 and was allowed to attain equilibrium at 423 K. Calculate the equilibrium composition of reaction mixture. (The Kc value for PCl5 dissociation at 423 K is 2)
4.
A sealed container was filled with 1 mol of A2 (g), 1 mol B2 (g) at 800 K and total pressure 1.00 bar. Calculate the amounts of the components in the mixture at equilibrium given that K = 1 for the reaction
A2 (g) + B2 (g) ⇌ 2AB (g)
5.
28 g of Nitrogen and 6 g of hydrogen were mixed in a 1 litre closed container. At equilibrium 17 g NH3 was produced. Calculate the weight of nitrogen, hydrogen at equilibrium.
1.
\(P_{CO_2}\) = 1.017 x 10-3 atm T = 500oC
Kp = \(P_{CO_2}\)
\(\therefore K_{P_1}\) = 1.017 x 10-3 T = 500 + 273 = 773 K
\(K_{P_2}\) = ? T = 600 + 273 = 873 K
\(\Delta H^o=181\ KJ\ mol^{-1}\)
\(\log({K_{P_1}\over K_{P_1}})={\Delta H^o\over 2.303\ R}({T_2-T_1\over T_1T_2})\)
\(\log({K_{P_2}\over 1.017\times 10^{-3}})={181\times 10^3\over 2.303\times 8.314}({873-773\over 873\times 773})\)
\(\log({K_{P_2}\over 1.017\times 10^{-3}})={181\times 10^3\times 100\over 2.303\times 8.314\times 873\times 773}\)
\({K_{P_2}\over 1.017\times 10^{-3}}=\) anti log of (1.40)
\({K_{P_2}\over 1.017\times 10^{-3}}=25.12\)
\(\Rightarrow K_{P_2}=\) 25.12 x 1.017 x 10-3
\(K_{P_2}=\) 25.54 x 10-3.
2.
CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g)
KC = 4 x 10–2 mol lit–2
Volume = 500 ml = 1/2 L
\(\left[\mathrm{CH}_{4}\right]_{\text {in }}=\frac{2 \mathrm{~mol}}{1 / 2 \mathrm{~L}} \)
= 2 mol L-1
\(\left[\mathrm{CS}_{2}\right]_{\text {in }}=\frac{1 \mathrm{~mol}}{1 / 2 \mathrm{~L}}\)
= 2 mol L-1
\( {\left[\mathrm{H}_{2} \mathrm{~S}\right]_{\text {in }}=\frac{2 \mathrm{~mol}}{1 / 2 \mathrm{~L}}=4 \mathrm{~mol} \mathrm{~L}^{-1} \quad\left[\mathrm{H}_{2}\right]=\frac{2 \mathrm{~mol}}{1 / 2 \mathrm{~L}}=4 \mathrm{~mol} \mathrm{~L}^{-1}} \)
\(\mathrm{Q}=\frac{\left[\mathrm{CS}_{2}\right]\left[\mathrm{H}_{2}\right]^{4}}{\left[\mathrm{CH}_{4}\right]\left[\mathrm{H}_{2} \mathrm{~S}\right]^{2}}=\frac{2 \times(4)^{4}}{(2) \times(4)^{2}}=16 \)
Q > Kc
\(\therefore \) The reaction will proceed in the reverse direction to reach the equilibrium.
3.
PCl5 ⇌ PCl3 + Cl2
Given that [PCl5]initial = 1 mol; V = 1 dm3; KC = 2
| PCl5 | PCl3 | Cl2 | |
| Initial no.of moles | 1 | - | - |
| No.of moles | x | - | - |
| No.of moles at equilibrium | 1 - x | x | x |
| Equilibrium concentration | \({1-x\over 1}\) | \({x\over 1}\) | \({x\over 1}\) |
\(K_c={[PCl_3][Cl_2]\over [PCl_5]}\)
\(2={x\times x\over (1-x)}\)
2 - 2x = x2|
x2 + 2x - 2 = 0
Solution for a quadratic equation
\(a x^{2}+b x+c=0 \text { are }, x=\frac{-b-\sqrt{b^{2}-4 a c}}{2 a}\)
a- = 1 b = 2 c = -2
\(x=\frac{-2-\sqrt{4-4 \times 1 \times-2}}{2 \times 1} \)
\(x=\frac{-2-\sqrt{12}}{2}=\frac{-2-\sqrt{4 \times 3}}{2}\)
\( x =\frac{-2-2 \sqrt{3}}{2} \)
\(=\frac{-2+2 \sqrt{3}}{2}, \frac{-2-2 \sqrt{3}}{2} \)
\(x =-1+\sqrt{3} ;-1-\sqrt{3} \)
\(=-1-\sqrt{3} \text { not possible } \)
Since x is + ve,
x = -1 + 1.732
x = 0.732
Equilibrium concentration of
\( {\left[\mathrm{PCl}_{5}\right]_{\mathrm{eq}}=\frac{1-x}{1}=1-0.732=0.268 \mathrm{M}} \)
\({\left[\mathrm{PCl}_{3}\right]_{\mathrm{eq}}=\frac{x}{1}=\frac{0.732}{1}=0.732} \)
\({\left[\mathrm{Cl}_{2}\right]_{\mathrm{eq}}=\frac{x}{1}=\frac{0.732}{1}=0.732} \)
4.
A2(g) + B2(g) ⇌ 2AB(g)
| A2 | B2 | AB | |
| Initial Concentration | 1 | 1 | - |
| No.of moles reacted | x | x | - |
| No.of moles at equilibrium | 1 - x | 1 - x | 2x |
Total no. of moles = 1 – x + 1 – x + 2x = 2
\(K_p={(P_{AB})^2\over (P_{A_2})(P_{B_2})}={({2x\over 2}\times p)^2\over ({(1-x)\over 2}\times p)({1-x\over 2}\times p)}\)
\(K_p={4x^2\over (1-x)^2}\)
Given that Kp = 1; \({4x^2\over (1-x)^2}=1\)
\(\Rightarrow \) 4x2 = (1 - x)2
\(\Rightarrow \) 4x2 = 1 + x2 - 2x
3x2 + 2x - 1 = 0
\(X={-2\pm\sqrt{4-4\times 3\times -1}\over 2(3)}\)
\(X={-2\pm\sqrt{4+12}\over 6}\)
\(={-2\pm\sqrt{16}\over 6}\)
\(={-2+4\over 6};{-2-4\over 6}\)
\(={2\over 6};{-6\over 6}\)
X = 0.33 ; -1 (not possible)
\(\therefore\) [A2]eq = 1 - x = 1 - 0.33 = 0.67
[B2]eq = 1 - x = 1 - 0.33 = 0.67
[AB]eq = 2X = 2 x 0.33 = 0.66.
5.
Given \(m_{N_2}\) = 28 g \(m_{H_2}\) = 6g
V = 1 L
\((n_{N_2})_{initial}={28\over 28}=1\ mol\)
\((n_{H_2})_{initial}={6\over 2}=3\ mol\)
N2(g) + 3H2(g) ⇌ 2 NH3(g)
| N2(g) | H2(g) | NH3(g) | |
| Initial concentration | 1 | 3 | - |
| Reacted | 0.5 | 1.5 | - |
| Equilibrium concentration | 0.5 | 1.5 | 1 |
\([NH_3]=({17\over 17})=1\ mol=1\ mol\)
Weight of N2 = (no. of moles of N2) × molar mass of N2
= 0.5 x 28 = 14 g
Weight of H2 = (no. of moles of H2) × molar mass of H2
= 1.5 x 2 = 3 g
11th Standard Syllabus & Materials
11th Standard
Tamilnadu 11th Standard Tamil பீடு பெற நில் - செய்யுள் - காவடிச்சிந்து Important Questions And Answers Study Material - QB365 Set A
NEW11th Standard
Tamilnadu 11th Standard Tamil பீடு பெற நில் - உரைநடை - மலை இடப்பெயர்கள் : ஓர் ஆய்வு Important Questions And Answers Study Material - QB365 Set B
NEW11th Standard
Tamilnadu 11th Standard Tamil பீடு பெற நில் - உரைநடை - மலை இடப்பெயர்கள் : ஓர் ஆய்வு Important Questions And Answers Study Material - QB365 Set A
NEW11th Standard
Tamilnadu 11th Standard Tamil மாமழை போற்றுதும் - செய்யுள் - ஐங்குறுநூறு Important Questions And Answers Study Material - QB365 Set B
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