1- Highest pH will be recorded for which of the following solutions if they are equimolar (PPSC 2017)?
a) AlCl3
b) LiCl
c) BeCl2
d) BaCl2
2- On increasing the concentration of reactants in a reversible reaction, then equilibrium constant will (PPSC 2020)?
a) depend on the concentration
b) increase
c) unchanged
d) decrease
3- For a specific reaction, which of the following statements can be made about K, the equilibrium constant? (PPSC 2017)?
a) It always remains the same at different reaction conditions
b) It increases if the concentration of one of the products is increased.
c) It increases if the concentration of one of the reactants is increased
d) It changes with changes in the temperature.
4- The pH of 10-3 mol dm-3 of an aqueous solution of H2SO4 is (PPSC 2021)?
a) 3
b) 2.7
c) 2
d) 1.5
5- Which buffer solution comprising of the following has its pH value greater than 7? (ppsc 2020)?
a) CH3COOH+CH3COONa
b) HCOOH+HCOOK
c) CH3COONH4
d) NH4OH+NH4Cl
6- The rate of a chemical reaction tells us about?
a) how slow or fast the reaction is taking place
b) the products formed in the reaction
c) the reactants taking part in the reaction
d) none of the above
7- The average rate and instantaneous rate of a reaction are equal?
a) at the start
b) at the end
c) in the middle
d) when two rates have a time interval equal to zero
8- The rate constant of zero-order reactions has the unit?
a) s-1
b) mol L-1 s-1
c) L2 mol-2 s-1
d) L mol-1 s-1
9- when the rate of the reaction is equal to the rate constant, the order of the reaction is (PPSC 2017)?
a) zero order
b) first order
c) second order
d) third order
10- In the Haber process for the manufacture of ammonia the following catalyst is used?
a) Platinized asbestos
b) Iron with molybdenum as a promoter
c) Copper oxide
d) Alumina
11- In the rate equation, when the concentration of reactants is unity then the rate is equal to?
a) specific rate constant
b) average rate constant
c) instantaneous rate constant
d) None of the above
12- In the reaction 2A + B → A2B, if the concentration of A is doubled and that of B is halved, then the rate of the reaction will (PPSC 2020)?
a) increase 2 times
b) increase 4 times
c) decrease 2 times
d) remain the same
13- Which of the following observations is incorrect about the order of a reaction?
a) The stoichiometric coefficient of the reactants doesn’t affect the order
b) Order of a reaction is always a whole number
c) Order of reaction is the sum of power to express the rate of reaction to the concentration terms of the reactants.
d) Order can only be assessed experimentally
14- When the system A + B C + D is at equilibrium,?
a) the sum of the concentrations of A and B must equal the sum of the concentrations of C and D.
b) the forward reaction has stopped.
c) the reverse reaction has stopped.
d) neither the forward nor the reverse reaction has stopped.
15- Consider the following reversible reaction. In a 3.00 liter container, the following amounts are found in equilibrium at 400 oC: 0.0420 mole N2, 0.516 mole H2 and 0.0357 mole NH3. Evaluate Kc. N2(g) + 3H2(g) <–> 2NH3(g)?
a) 0.202
b) 16.0
c) 1.99
d) None of these
16- At 445oC, Kc for reaction is 0.020., 2HI(g) <—> H2(g) + I2(g) then, A mixture of H2, I2, and HI in a vessel at 445oC has the following concentrations: [HI] = 2.0 M, [H2] = 0.50 M and [I2] = 0.10 M, then Qc, is TRUE for?
a) Qc = Kc; the system is at equilibrium.
b) Qc is less than Kc; more H2 and I2 will be produced.
c) Qc is less than Kc; more HI will be produced.
d) Qc is greater than Kc; more H2 and I2 will be produced.
17- Consider the equilibrium system:, 2ICl(s) <—-> I2(s) + Cl2(g), Which of the following changes will increase the total amount of of Cl2 that can be produced??
a) removing the Cl2 as it is formed
b) adding more ICl(s)
c) removing some of the I2(s)
d) all of the above
18- What is the equilibrium constant for a reaction that has a value of Go = -41.8 kJ at 100 degree??
a) 1.01
b) 7.1 x 105
c) -5.87
d) 1.4 x 10-6
19- Which of following change will favour the formation of more HI in the given reaction, H2 + I2 <—–>2HI?
a) increasing pressure
b) decreasing pressure
c) by adding more HI
d) by adding more H2 and I2
20- When pressure is applied to the given equilibrium ice water which of the following will happen?
a) more ice will be formed
b) more water will be formed
c) equilibrium will not be disturbed
d) water will formed
