11th Standard CBSE Syllabus & Materials
11th Standard CBSE
CBSE 11th Economics PART-A - Presentation of Data - New Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Economics PART-A - Organisation of Data - New Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Economics PART-A - Collection of Data - New Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Economics PART-A - Introduction to Economics and Statistics - New Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Business Studies International Trade Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Business Studies Evolution and Fundamentals of Business Sample Question Papers Study Material - QB365 Set A

Published on: 05/09/2019
Equilibrium
Download CBSE Class 11th Standard CBSE Chemistry question papers, sample papers, important questions, and previous year solved papers in PDF format. Get free study materials, NCERT solutions, and exam preparation resources for Class 11th Standard CBSE Chemistry
Questions + Answers key
Take MCQ Chemistry Test

1.
pKa value of acids A,B,C,D are 1.5, 3.5, 2.0 and 5.0.Which of them is strongest acid?
2.
For the following equilibrium, Kc = \(6.3\times { 10 }^{ 14 }\) at 1000 K
\(NO(g)+{ O }_{ 3 }(g)\rightleftharpoons NO_{ 2 }(g)+{ O }_{ 2 }(g)\) Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is Kc , for the reverse reaction?
3.
What will be the PH of 0.1 M ammonium acetate solution?\(P{ k }_{ a }=P{ k }_{ b }=4.74\)
4.
The value of Kc for the reaction, \({ 3O }_{ 2 }(g)\rightleftharpoons { 2O }_{ 3 }(g)\) is 2.0 ×10–50 at 25°C. If the equilibrium concentration of O2 in air at 25°C is 1.6 ×10–2, what is the concentration of O3?
5.
Under the conditions is a substance precipitated from its solution?
6.
What is the expression for \({ k }_{ sp } \ of \ { Ag }_{ 2 }Cr{ 0 }_{ 4 }?\)
7.
The solubility product of silver bromide is 3.3 x 10-13 Calculate its solubility.
8.
A tank is full of water. Water is coming in as well as going out at same rate. What will happen to level of water in a tank? What is name given to such a state?
9.
Calculate the pH of a buffer which is 0.1 M in acetic acid and 0.15 M in sodium acetate. Given that the ionisation costants of acetic acid is 1.75 x 10-5. Also calculate the change in pH of the buffer if to 1L of the buffer 1 cc of 1 M NaOH are added.
10.
The following concentrations were obtained for the formation of NH3 from N2 and H2 at equilibrium at 500K. [N2] = 1.5 × 10–2M. [H2] = 3.0 × 10–2 M and [NH3] = 1.2 × 10–2M. Calculate equilibrium constant.
11.
Equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate are mixed together. Will it lead to precipitation of copper iodate? (For cupric iodate \(K_{sp}\) = 7.4 x \(10^{-8}\))
12.
The solubility product of Agcl is 1.5\( \times10^{-10}\)Predict whether there will be any precipitation by mixing 50ml of 0.01 MAgno3 solution.
13.
At 298 K, a 0.1M solution of acetic acid is 1.34% ionised. What is the ionisation constant Ka of acetic acid?
14.
What is the minimum volume of water required to dissolve 1g of calcium sulphate at 298 K? (For calcium sulphate, Ksp is 9.1 x 10-6).
15.
Calculate the pH of the resultant mixtures 10 mL of 0.01 M H2SO4+10 mL of 0.01 M Ca(OH)2
16.
The species: H2O,HCO3- ,HSO4- and NH3 can act both as Bronsted acids and bases. For each case give the corresponding conjugate acid and conjugate base.
1.
Acid A with pKa = 1.5 is strongest acid , Lower the value of pKa stronger will be the acid.
2.
For the reaction
\(NO(g)+{ O }_{ 3 }(g)\rightleftharpoons NO_{ 2 }(g)+{ O }_{ 2 }(g)\)
\(({ K }_{ c }=6.3\times { 10 }^{ 14 }at\quad 1000K)\)
\({ K }_{ c }=\frac { [{ NO }_{ 2 }][{ O }_{ 2 }] }{ [NO][{ O }_{ 3 }] } =6.3\times { 10 }^{ 14 }\) ...(i)
For reverse reaction,
\(NO_{ 2 }(g)+{ O }_{ 2 }(g)\rightleftharpoons NO(g)+{ O }_{ 3 }(g)\)
\({ K }'_{ c }=\frac { [{ NO }][{ O }_{ 3 }] }{ [NO_{ 2 }][{ O }_{ 2 }] } \) ...(ii)
From Eqs. (i) and (ii) we, get
\({ K }'_{ c }=\frac { 1 }{ { K }_{ c } } =\frac { 1 }{ 6.3\times { 10 }^{ 14 } } =1.587\times { 10 }^{ -15 }\)
3.
\(pH=\cfrac { 1 }{ 2 } p{ k }_{ w }+\cfrac { 1 }{ 2 } p{ k }_{ a }-\cfrac { 1 }{ 2 } p{ K }_{ b }\)
\(=\cfrac { 1 }{ 2 } (14)+\cfrac { 1 }{ 2 } (4.75)-\cfrac { 1 }{ 2 } (4.74)=7\)
4.
\({ 3O }_{ 2 }(g)\rightleftharpoons { 2O }_{ 3 }(g)\quad \)
\({ K }_{ c }=\frac { \left[ { O }_{ 3 } \right] ^{ 2 } }{ \left[ { O }_{ 2 } \right] ^{ 3 } } \)
or \({ O }_{ 3 }=\sqrt { { K }_{ c }\left[ { O }_{ 2 } \right] } ^{ 3 }=\sqrt { (2.0\times { 10 }^{ -50 })(1.6\times { 10 }^{ -2 })^{ 3 } } \)
\(\left[ { O }_{ 3 } \right] =2.86\times { 10 }^{ -28 }mol{ L }^{ -1 }\)
5.
Precipitation takes place when ionic product exceeds the solubility product.
6.
\(\mathrm{Ag}_2 \mathrm{CrO}_4(s) \rightleftharpoons 2 \mathrm{Ag}^{+}(a q)+\mathrm{Cro}_4^{2-}(a q)\)
\(K_{\text {sp }}=\left[\mathrm{Ag}^{+}\right]^2\left[\mathrm{Cro}_4^{2-}\right]=(2 s)^2(s)=4 s^3\)
7.
\( A g B r \rightarrow[A g][B r]\)
\( k s p \rightarrow(s) \times(s) \)
\( k s p=s^2 \)
\(s=\sqrt{k s p}=\sqrt{3.3 \times 10^{-3}} \)
\( =5.477 \times 10^{-7}
\)
= 5.7 x 10-7 mol L-1
8.
It will remain the same because rate of inflow is equal to rate of outflow. The state is called of 'equilibrium'.
9.
\(pH={ pK }^{ a }+\log { \frac { \left[ Salt \right] }{ \left[ Acid \right] } } =-\log { \left( 1.75\times { 10 }^{ -5 } \right) } +\log { \frac { 0.15 }{ 0.10 } } \quad \)
= (5 - 0.2430) + 0.1761 =4.757 + 0.1761 = 4.933
1 cc of 1 M NaOH contains NaOH = 10-3 mol. This will convent 10-3 mol of acetic acid into the salt so that salt formed = 10-3 mol.
Now, [Acid] = 0.10 - 0.001 = 0.099 M
[Salt] = 0.15 + 0.001 = 0.151 M
pH = 4.757 + \(\log { \frac { 0.151 }{ 0.099 } } \)
= 4.757 + 0.183 =4.940
Increase in pH = 4.940 - 4.933 = 0.007 which is negligible.
10.
The equilibrium constant for the reaction,
\({ N }_{ 2 }(g)+3{ H }_{ 2 }(g)\rightleftharpoons 2{ NH }_{ 3 }(g)\) can be written as,
\( { K }_{ c }=\frac { \left[ { NH }_{ 3 }(g) \right] ^{ 2 } }{ \left[ { N }_{ 2 }(g) \right] \left[ { H }_{ 2 }(g) \right] ^{ 3 } } \)
\({ K }_{ c }=\frac { \left( 1.2\times { 10 }^{ -2 } \right) ^{ 2 } }{ \left( 1.5\times { 10 }^{ -2 } \right) \left( 3.0\times { 10 }^{ -2 } \right) ^{ 3 } } \)
= 0.106 × 104 = 1.06 × 103
11.
\(2NaI{ O }_{ 3 }+Cu(CIo_{ 3 }{ ) }_{ 2 }\longrightarrow 2NaCl{ O }_{ 3 }+Cu(I{ O }_{ 3 }{ 0 }_{ 2 }\)
\([C{ u }^{ 2+ }{ ] }_{ mix }=\cfrac { 0.002 }{ 2 } =0.001M\)
\( [I{ O }_{ 3 }^{ - }{ ] }_{ mix }=\cfrac { 0.002 }{ 2 } =0.001M\)
\(Cu(I{ O })_{ 3 }\rightleftharpoons C{ u }^{ 2+ }+2I{ o }_{ 3 }^{ - }\)
\( [C{ u }^{ 2+ }{ ] }[I{ O }_{ 3 }^{ - }{ ] }=(1.0\times { 10 }^{ -3 })\times (1.0\times { 10 }^{ -3 }{ ) }^{ 2 }=1\times { 10 }^{ -9 }\)
\(Ionic\quad product<{ K }_{ sp }\)
12.
On mixing 50ml of 0.01 M NaCl and 50 ml of 0.01 M AGNO3, the total volume become 100 ml
Conc.of NaCl in 100 ml = \(\cfrac { 0.01\times 50 }{ 100 } =0.005M\)
Conc.Of AgN\(O_{3}\)in 100 ml = \(\cfrac { 0.01\times 50 }{ 100 } =0.005M\)
\(NaCl(aq)={ Na }^{ + }(aq)+{ Cl }^{ - }(aq)\)
\( [{ Cl }^{ - }]=[NacL]=0.005N\)
\( [Ag^{ + }]=[AgN{ O }_{ 3 }]=0.005M\)
\(Ionic \ product \ of \ [A{ g }^{ + }]=[{ Cl }^{ - }]=0.0005\times 0.0005=2.5\times { 10 }\)
Since ionic product is greater than its solubility product, precipitation will occur.
13.
The degree of ionisation \((\alpha)=1.34 \%=\frac{1.34}{100}=0.0134\) The ionisation of acetic may be represented as :
\(\begin{array}{l}
\mathrm{CH}_3 \mathrm{COOH} \\
\mathrm{C}(1-\alpha)
\end{array} \begin{array}{l}
\leftrightarrow \mathrm{CH}_3 \mathrm{COO}^{-} + H^{+}\\
\mathrm{C} \alpha \ \ \ \ \ \ \ \ \ \ \ \mathrm{C} \alpha
\end{array} \)
\({\left[\mathrm{CH}_3 \mathrm{COO}^{-}\right]=\mathrm{C} \alpha=0.1 \times 0.0134=0.00134 \mathrm{M} \text {, }} \)
\( {\left[\mathrm{H}^{+}\right]=C \alpha=0.1 \times 0.0134=0.00134 M} \)
\({\left[\mathrm{CH}_3 \mathrm{COOH}\right]=\mathrm{C}(1-\alpha)=0.1(1-0.0134)} \)
\( =0.09866 \mathrm{M} \)
\( K_a=\frac{\left[\mathrm{CH}_3 \mathrm{COO}^{-}\right]\left[\mathrm{H}^{+}\right]}{\left[\mathrm{CH}_3 \mathrm{COOH}\right]} \)
\( =\frac{(0.00134) \times(0.00134)}{0.09866}=1.82 \times 10^{-5} \)
14.
\({ CaSO }_{ 4 }\rightleftharpoons { Ca }^{ 2+ }+{ SO }_{ 4 }^{ 2- };{ K }_{ sp }=9.1\times { 10 }^{ -6 }\)
S S S
Where s is the solubility of CaSO4
\({ K }_{ sp }=\left[ { Ca }^{ 2+ } \right] \left[ { SO }_{ 4 }^{ 2- } \right] =S.S={ S }^{ 2 }\)
\(S=\sqrt { { K }_{ sp } } =\sqrt { 9.1\times { 10 }^{ -6 } } \Rightarrow S=3.017\times { 10 }^{ -3 }M\)
Solubility of CaSO4 = 3.017 x 10-3 mol-1
= 3.017 x 10-3 x 136 gL-1
(Molar mass of CaSO4 =136 g mol-1)
= 410.3 x 10-3 gL-1
410.3x10-3 g CaSO4 is dissolved in = 1L
1g CaSO4 is dissolved in = \(\frac { 1\times 1 }{ 410.3\times { 10 }^{ -3 } } \) = 2.437 L
15.
\(Millimoles \ of \ acid, \ { H }_{ 2 }{ SO }_{ 4 }={ M }_{ 1 }{ V }_{ 1 }=2\times 0.01\times 10=0.2\)
\( Millimoles \ of \ base,\ Ca({ OH }_{ 2 })={ M }_{ 2 }{ V }_{ 2 }\)
\(=2\times 0.01\times 10=0.2\)
\( \therefore { M }_{ 1 }{ V }_{ 1 }={ M }_{ 2 }{ V }_{ 2 } \ hence \ solution \ is \ neutral.\)
\( \therefore pH=7\)
16.
The answer is given in the following Table :
| Species | Conjugate acid | Conjugate base |
| H2O | H3O+ | OH- |
| HCO3- | H2CO3 | CO32- |
| HSO4- | H2SO4 | SO42- |
| NH3 | NH4+ | NH2- |
11th Standard CBSE Syllabus & Materials
11th Standard CBSE
CBSE 11th Business Studies Forms of Business Organisation Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Business Studies Business, Trade and Commerce Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Physics Waves Sample Question Papers Study Material - QB365 Set A
NEW11th Standard CBSE
CBSE 11th Physics Kinetic Theory Sample Question Papers Study Material - QB365 Set A
CBSE 11th Standard CBSE Subjects
CBSE Standards