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Published on: 25/10/2025
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1.
Calculate the overall order of a reaction which has the rate expression
(a) Rate = k [A] 1/2 [B]3/2
(b) Rate = k [A]3/2 [B]-1
2.
What is the amount of charge required to carry out the conversion of 1 mole of Al3+ions to Al according to the following reaction,
Al3++ 3e- Al
3.
The rate constant for a second order reaction is k = \(\frac {2.303}{t(a-b)} log \frac {b(a-x)}{(b-x)}\)where a and b are initial concentrations of the two reactants A and B involved. If one of the reactants is present in excess, it becomes pseudo unimolecular. Explain how ?
4.
What is the relation between normality and molarity of a given solution of H2SO4 ?
5.
Define specific conductivity (specific conductance).
6.
The elevation in boiling point of 0.1 molal solution of X in water is 0.1536 oC. What conclusion do you draw about the molecular state of X?
[Given : Kb = 0.512 k kg mol-1]
7.
Discuss biological and industrial importance of osmosis.
8.
A voltaic cell is set up at 25°C with the following half-cells.
AI IAI3+(0.001M) and Ni Ni2+ (0.50 M)
Write an equation for the reaction that occurs when the cell generates an electric current and determine the cell potential.
\(E^{ 0 }_{ Ni2+/Ni }=-0.25V\) and (log 8 x 10-6=-5.0969)
9.
The inversion of cane sugar was studied in 1N HCl at 298K. The following polarimetric were obtained at different intervals of time:
| Time(minutes): | 0.0 | 7.18 | 18.00 | 27.05 | \(\infty\) |
| Reading (degree): | +24.09 | +21.41 | +17.74 | +15.00 | -10.74 |
Show that the inversion of cane sugar is a unimolecular reaction.
10.
The initial rate of reaction A+5B+6C\(\longrightarrow\)3L+3M has been determined by measuring the rate of disappearance of A under the following condition:
| Expt.No | [A]0/M | [B]0/M | [C]0/M | Initial rate/M min-1 |
| 1 | 0.02 | 0.02 | 0.02 | 2.08\(\times\)10-3 |
| 2 | 0.01 | 0.02 | 0.02 | 1.04\(\times\)10-3 |
| 3 | 0.02 | 0.04 | 0.04 | 4.16\(\times\)10-3 |
| 40.02 | 0.02 | 0.02 | 0.04 | 8.32\(\times\)10-3 |
Determine the order of reaction with respect to each and overall order of the reaction.What is the rate constant?Calculate the initial rate of change in concentration of B and L
11.
At 291 K, Satured solution of BaSO4 was found to have a specific conductivity of 3.648 \(\times\) 10-6 ohm-1 cm-1, that of water used being 1.25 \(\times\) 10-6 ohm-1 cm-1. Ionic conductances of Ba2+ and SO2-4 ions are 110 and 136.6 ohm-1cm2 mol-1 respectively. Calculate the solubility of BaSO4 at 291 K. (At masses : Ba = 137, S = 32,O = 16)
12.
A solution of urea in water has a boiling point of 373.128 K. Calculate the freezing point of the same solution. [Given: For water, K f = 1.86 Km-1, Kb = 0.52 Km-1]
13.
The Pgas dissolved a liquid is directly proportion to its
mole fraction
molar mass
boiling point of liquid
molar mass of solvent
14.
In the first order reaction the concentration of reactant decreases from 0.6 M to 0.3 M in 30 minutes. The time taken for the concentration to change from 0.1 M to 0.025 M:
60 min
30 min
15 min
50 min
15.
After introducing the factor P, expression for the rate of a reaction, becomes
\(Rate =\frac{Z_{A B} e^{-E_{a} / R T}}{P}\)
\( Rate =P Z_{A B} e^{-E_{a}/RT}\)
\( Rate =\frac{Z_{A B}.P}{e^E_{a}/RT}\)
\(Rate=\frac{e^{E_{a} / R t}}{P Z_{AB}}\)
16.
Consider the data given below for a hypothetical reactions, M ⟶ N
| Time(s) | Rate of reaction (mol L-1 s-1) |
| 0 | 4.20 x 10-4 |
| 10 | 4.20 x 10-4 |
| 20 | 4.20 x 10-4 |
| 30 | 4.20 x 10-4 |
| 40 | 4.18 x 10-4 |
For the above data, the order of reaction is
one
two
three
zero
17.
1.5A current is flowing through a metallic wire. If it flows for 3 hrs, how many electrons would flow through the wire?
2.05x1022electrons
1.0 x1023 electrons
1024electrons
4.5x1023 electrons
18.
An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to
Increase in number of ions
Increase in ionic mobility of ions
100% ionisation of electrolyte at normal dilution
Increase in both, i.e., number of ions and ionic mobility of ions
19.
Two faradays of electricity are passed through a solution of CuSO4. The mass of copper deposited at the cathode (at mass of Cu = 63.5 amu)
2 g
127 g
0 g
63.5 g
20.
Which statements are true about osmotic pressure (\(\pi \) )volume (V) and temperature (T) ?
\(\pi \alpha \frac { 1 }{ V } if \ T \ is \ constant\)
\(\pi \alpha T\quad if \ V \ is \ constant\)
\(\pi \alpha V \ if \ T \ is \ costant\)
\(\pi V \ is \ constant \ if \ T \ is \ constant\)
21.
The pH of 1 M solution of a weak monobasic acid (HA) is 2. Then, the van't Hoff factor is
1.01
1.02
1.10
1.20
22.
To neutralise completely 20 mL of 0.1 M aqueous solution of phosphorous acid (H3PO3), the volume of 0.1 M aqueous KOH solution required is
10 mL
20 mL
40 mL
60 mL
23.
(a) What is the rate of reaction? Write two factors that affect the rate of reaction
(b) The rate constant of a first-order reaction increase from 4 x 10- 2 to 8 x 10-2 when the temperature changes from 27°C to 37°C. Calculate the energy of activation (Ea). log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021.
24.
(i) Write the chemistry of discharging the Leclanche cell, highlighting all the materials that are involved during cell reactions. State its use.
(ii) What is the difference between primary and secondary cells? Differentiate using their applications also.
(iii) Prevention of corrosion is of prime importance. Comment.
25.
Discuss the products obtained in electrolysis of aqueous solution of brine.
26.
What is the solubility of a solid in liquid? Describe the various factors on which the solubility of a solid in a liquid depends?
27.
(i) What type of deviation is shown by a mixture of ethanol and acetone? Give reason.
(ii) A solution of glucose (molar mass = 180 g mol-1) in water is labelled as 10 % (by mass). What would be the molality and molarity of the solution?
(Density of solution = 1.2 g mL-1)
28.
Two first reactions proceed at the same rate at 15oC when started with same initial concentration. The temperature coefficient of the first reaction is 2 while that of the second reaction is 3. What will be the ratio of the rates of these reactions at 55oC ?
1.
\(\text { (a) } \frac{1}{2}+\frac{3}{2}=2\)
\(\text { (b) } \frac{3}{2}-1=\frac{1}{2}\)
2.
The number of electrons involved in the reaction is three.
Therefore, the amount of electricity required for one mole
of AI3+ ions = 3F or 3 x 96500C = 289500C
3.
Suppose B is in excess so that b>> a or x. Neglecting a and x in comparison to b, the equation reduced to k b = k' = \(\frac {2.303}{t} log \frac {a}{(a-x)}\) which is same as for reactions of 1st order.
4.
Normality = 2 × Molarity.
5.
Specific conductance is defined as conductance of electrolyte when distance between electrodes is 1 cm and area of cross section is 1 cm2 .
6.
\(\Delta T_{b}\) = Kb x m = 0.512 x 0.1 = 0.0512,
i = \(\frac{\text { observed } \Delta \mathrm{T}_{b}}{\text { normal } \Delta \mathrm{T}_{b}}=\frac{0.1536}{0.0512}=3\)
Solute undergoes dissociation in water. It is a strong electrolyte.
7.
(i) The process of osmosis is of great biological and industrial importance as is evident from the following examples:
(ii) Movement of water from the soil into plant roots and subsequently into the upper portion of the plant occurs partly due to osmosis.
(iii) Preservation of meat against bacterial action by adding salt.
(iv) Preservation of fruits against bacterial action by adding sugar. The bacterium in canned fruit loses water through the process of osmosis, shrivels and dies.
(v) Reverse osmosis is used for the desalination of water.
8.
(i) Calculate E0cell by using the formula
\(E^{ 0 }_{ cell }=E^{ 0 }_{ cathode }-E^{ 0 }_{ anode }\)
(ii) Calculate the number of electrons by writing the electrode reactions then write Nernst equation and find Ecell
For the cell A1|A13+||Ni2+|Ni
(0.001M) (0.50M)
the cell reaction is
\(2AI(s)+3Ni^{ 2+ }(aq)\longrightarrow 2AI^{ 3+ }(aq)+3Ni(s)\)
Thus n=6
\(E^{ 0 }_{ cell }=E^{ 0 }_{ Ni^{ 2+ }/Ni }-E^{ 0 }_{ A13+/A1 }\)
= - 0..25 V- (- 1.66 V) = 1.41 V
\(E_{ cell }=E^{ 0 }_{ cell }=\frac { 0.0591 }{ n } log\frac { \left[ A1^{ 3+ } \right] ^{ 2 } }{ \left[ Ni^{ 2+ } \right] ^{ 3 } } \)
\(E_{ cell }=1.14V-\frac { 0.0591V }{ 6 } log\frac { \left( 10^{ -3 } \right) ^{ 2 } }{ \left( 0.50 \right) ^{ 3 } } \)
\(=1.41V-\frac { 0.0591V }{ 6 } log\frac { 8\times 10^{ 6 } }{ 1 } \left( \therefore \frac { 1 }{ 0.125 } =8 \right) \)
\(E_{ cell }=1.41V-\frac { 0.0591V }{ 6 } \times \left( -5.0969 \right) \)
= 1.41 V + 0..0.50.2 V= 1.460.2 V
9.
The constancy in the value of k proves that the reaction is of the first order.
10.
Rate = k[A0][B0][C0]2,Overall order=1 + 1 + 2 = 4,k = 1.3\(\times\)10-4 M-2 min-1 d[B]/dt = -1.04\(\times\)10-2M min-1,d[L]/dt = 6.24\(\times\)10-3M min-1.
11.
2.266 \(\times\) 10-3 gL-1
12.
\(\triangle { T }_{ b }=373.128 \ K-373.0 \ K=0.128 \ K\)
\(\\ \triangle { T }_{ b }={ K }_{ b } \ \times \ m\)
\( \Rightarrow m=\frac { 0.128 }{ 0.52 } =0.246 \ mol/kg\)
\( Now,\triangle { T }_{ f }={ K }_{ f } \ \times \ m=1.86\times0.246=0.457\)
Freezing point = \(273-0.457=272.543 \ K\)
13.
(a)
mole fraction
14.
(a)
60 min
15.
(b)
\( Rate =P Z_{A B} e^{-E_{a}/RT}\)
16.
(d)
zero
17.
(b)
1.0 x1023 electrons
18.
(b)
Increase in ionic mobility of ions
19.
(c)
0 g
20.
(a)
\(\pi \alpha \frac { 1 }{ V } if \ T \ is \ constant\)
21.
(a)
1.01
22.
(c)
40 mL
23.
(a) Rate of reaction is defined as the change in concentration of reactants or products per unit time. Factors that affect rate of a reaction
(i) Concentration of reactant
(ii) Temperature
\(log{k_2\over k_1}={E_a\over 2.303R}\left[T_2-T_1\over T_1T_2\right]\)
k1 = 4 x 10-2 k2
T1= 8 x 10-2,
T1 = 273 + 27 = 300K
T2 = 273 + 37 = 310K,
R = 8.314 JK-1mol-1
\(log{2\times10^{-2}\over 4\times10^{-2}}={E_a\over 2.303\times8.314}\left[310-300\over 300\times310\right]\)
\(log2={E_a\over 2.303\times8.314}\times{10\over 300\times310}\)
\(0.301={E_a\over 2.303\times8.314}\times{10\over 300\times310}\)
\(E_a={0.301\times2.3038.314\times300\times 310\over 10}\)
= 53598 J mol-1
= 53.598 kJ mol-1
24.
(ii)The major difference between a primary cell and the secondary cell is that primary cells are the ones that cannot be charged but secondary cells are the ones that are rechargeable.
(iii) Preventions of corrosion :
(1) Barrier protection :
(a) By painting the surface of metal
(b) By coating the surface with thin film of oil or grease.
(c) By electroplating iron with non corrosive metal.
(2) Sacrificial protection :
In this method iron is coated with a layer of metal more active than iron.
(3) Electrical Protection.
(4) Using anti - rust solutions.
25.
The products of an aqueous solution of NaCl or brine are NaOH, Cl2, and H2.
In this reaction, NaCl and H2O both dissociate as forming chlorine and hydrogen gas and caustic soda.
NaCl ⇾ Na+ + Cl-
H2O ⇾ H++OH-
Uses:
1. Sodium hydroxide is used in the manufacturing of soap, paper pulp, and petroleum products.
2. Chlorine gas is used as a disinfectant to kill germs and bacteria in water.
3. Hydrogen gas is used in the production of hydrochloric acid and welding.
26.
Solubility of Solids In Liquids:
Solubility is the interaction between particles of the solute and the solvent. Hence, it depends on the nature of the solute and the solvent, as well as on the temperature and pressure. But the solubility of solids in liquids is independent of pressure.
Factors affecting solubility
1. Temperature. Basically, solubility increases with temperature.
2. Polarity. In most cases solutes dissolve in solvents that have a similar polarity.
3. Pressure. Solid and liquid solutes.
4. Molecular size.
5. Stirring increases the speed of dissolving.
27.
(i) It shows positive deviation.
It is due to weaker interaction between acetone and ethanol than ethanol-ethanol interactions.
(ii) Given : WB = 10g, Ws = 100 g, WA = 90 g, MB = 180 g.mol and d = 1.2 g/mL
\(M=\frac { Wt%\times density\times 10 }{ Mol.wt } \)
\(M=\frac { 10\times 1.2\times 10 }{ 180 } \)
= 0.66 M or 0.66 mol/L
\(m=\frac { { W }_{ B }\times 1000 }{ { M }_{ B }\times { W }_{ A }(in\quad g) } \)
\(m=\frac { 10\times 1000 }{ 180\times 90 } \)
= 0.61 m or 0.61 mol/kg
(or any other suitable method)
28.
If RI is the rate of first reaction at 25°C, then as its temperature coefficient is 2, its rate at 35°C will be = 2 R1, at 45°C = 2 x 2 R1 = 4 R1 and at 55°C = 2 x 4 R1 = 8 R1
If R2.is the rate of the second reaction at 25°C, then as its temperature coefficient is 3, its rate at 35°C will be = 3 R2, at 45°C = 3 x 3 R2 = 9 R2 and at 55°C = 3 x 9 R2 = 27 R2
Also, we are given R1 = R2, i.e., at 25°C, the rates are equal.
At 550C, \({Rate\ of\ 2nd\ reaction\over Rate\ of\ 1st\ reaction}={27R_2\over 8R_1}={27\over 8}\)
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