1.
In a reaction, A + B Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law for the reaction can be written as:
Correct Answer
B. Rate = k [A]2 [B]
Explanation
The given information states that when the concentration of B is doubled, the rate is also doubled. This suggests that the rate is directly proportional to the concentration of B. Additionally, when the concentrations of both reactants A and B are doubled, the rate increases by a factor of 8. This indicates that the rate is directly proportional to the concentration of both A and B. Therefore, the rate law for the reaction can be written as Rate = k [A]2 [B], where k is the rate constant.
2.
A reaction involving two different reactants can never be:
Correct Answer
A. Unimolecular Reaction
Explanation
A unimolecular reaction involves the decomposition or rearrangement of a single molecule. It does not involve the interaction between two different reactants. Therefore, a reaction involving two different reactants can never be a unimolecular reaction.
3.
The conversion of molecules X and Y follows second order kinetics. If concentration of X is increased to three times, how will it affect the rate of formation of Y?
Correct Answer
B. Increase the rate of time for the conversion of X to Y.
Explanation
When the concentration of X is increased to three times, it will lead to an increase in the rate of formation of Y. This is because the conversion of X and Y follows second order kinetics, which means that the rate of the reaction is directly proportional to the square of the concentration of X. Therefore, when the concentration of X is increased, the rate of formation of Y will also increase.
4.
The rate of reaction between two reactants A and B decreases by a factor of 4 if the concentration of reactant B is doubled. The order of reaction with respect to reactant B is:
Correct Answer
C. -2
Explanation
The rate of reaction between reactants A and B is said to decrease by a factor of 4 when the concentration of reactant B is doubled. This suggests that the rate of reaction is inversely proportional to the concentration of reactant B. In other words, as the concentration of B increases, the rate of reaction decreases. This indicates that the reaction is second order with respect to reactant B. Therefore, the answer is -2.
5.
If a reaction is 50% complete in 2 hours and 75% complete in 4 hours. What is the order of the reaction:
Correct Answer
A. First order reaction
Explanation
The given information states that the reaction is 50% complete in 2 hours and 75% complete in 4 hours. In a first-order reaction, the rate of reaction is directly proportional to the concentration of the reactant. As the reaction progresses, the concentration of the reactant decreases exponentially. The fact that the reaction is 50% complete in 2 hours and 75% complete in 4 hours suggests that the reaction is proceeding at a constant rate, indicating a first-order reaction.
6.
Consider a reaction, aG + bH Products.
When concentration of both the reactants G and H is doubled, the rate increases by eight times. However, when the concentration of G is doubled keeping the concentration of H fixed, the rate is doubled. The overall order of the reaction is:
Correct Answer
D. 3
Explanation
In this reaction, when the concentration of both reactants G and H is doubled, the rate increases by eight times. This suggests that the rate is directly proportional to the square of the concentration of both reactants. Furthermore, when the concentration of G is doubled while keeping the concentration of H fixed, the rate is doubled. This indicates that the rate is directly proportional to the concentration of G. Therefore, the overall order of the reaction is 3, which means that the rate is proportional to the cube of the concentration of G and H.
7.
A reaction was found to be second order with respect to concentration of carbon monoxide. If the concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction will:
Correct Answer
B. Increase by factor of 4
Explanation
In a second-order reaction, the rate of the reaction is directly proportional to the square of the concentration of the reactant. Therefore, if the concentration of carbon monoxide is doubled, the rate of the reaction will increase by a factor of 2^2, which is 4. This means that the rate of the reaction will increase by a factor of 4.
8.
The rate of a chemical reaction doubles for every 10°C rise of temperature. If the temperature is raised by 50°C, the rate of the reaction increases by about:
Correct Answer
C. 32 times
Explanation
The rate of a chemical reaction is known to double for every 10°C rise in temperature. Therefore, for a 50°C rise in temperature, the rate of the reaction would double 5 times (50°C/10°C = 5). Since the rate doubles each time, the rate of the reaction would increase by 2^5 = 32 times.
9.
When a bio chemical reaction is carried out in laboratory; outside the human body in the absence of enzyme, then the rate of reaction obtained is 10–6 times, than activation energy of reaction in the presence of enzyme is:
Correct Answer
C. Different from Ea obtained in laboratory
Explanation
When a biochemical reaction is carried out in the laboratory without the presence of an enzyme, the rate of reaction obtained is different from the activation energy (Ea) obtained in the laboratory. This suggests that the presence of an enzyme significantly affects the rate of reaction. Enzymes lower the activation energy barrier, allowing the reaction to occur at a faster rate. Therefore, the activation energy in the presence of an enzyme is different from the activation energy obtained in the laboratory without the enzyme.
10.
Which of the following statement for order of reaction is not correct?
Correct Answer
B. Order of a reaction is equal to the sum of the power of concentration terms in differential rate law
Explanation
Order of a reaction is equal to the sum of the power of concentration terms in differential rate law.
This statement can be misleading because it suggests that the order is directly related to the stoichiometric coefficients, which is not necessarily true. The order of a reaction must be determined experimentally and is not always equal to the sum of the stoichiometric coefficients in the balanced chemical equation.
11.
For the reaction:
2A + B 3C + D
Which of the following does not express the reaction rate?
Correct Answer
C.
Explanation
The reaction rate is the speed at which reactants are consumed or products are formed. In this case, the options provided are expressions for the reaction rate. Therefore, it is not possible to determine which of the options does not express the reaction rate without knowing the options themselves.
12.
Predict the order of reaction, looking onto the figure:
Correct Answer
B. One
Explanation
The graph illustrates a linear relationship between the rate of reaction and the concentration of the reactant, indicating that the rate increases directly in proportion to the concentration. This pattern is characteristic of a first-order reaction, where the reaction rate is directly proportional to the concentration of one reactant. Therefore, the order of the reaction depicted in the graph is first-order.
13.
A follows first-order reaction, (A) product
Concentration of A, changes from 0.1 M to 0.025 M in 40 minutes. Find the rate of reaction of A when the concentration of A is 0.01 M.
Correct Answer
D. 3.47 x 10-4 M min-1
Explanation
The rate of reaction can be determined using the first-order reaction rate equation, which is rate = k[A]. Given that the concentration of A changes from 0.1 M to 0.025 M in 40 minutes, we can use this information to calculate the rate constant (k) using the integrated rate law for a first-order reaction. Once we have the rate constant, we can plug in the concentration of A (0.01 M) into the rate equation to find the rate of reaction. The correct answer, 3.47 x 10^-4 M min-1, is obtained by performing these calculations.
14.
In the reaction:
BrO3– (aq) + 5Br– (aq) + 6H+ 3Br2 (l) + 3H2O(l)
The rate of appearance of bromine (Br2) is related to the rate of disappearance of bromide ions as
Correct Answer
D.
Explanation
The rate of appearance of bromine (Br2) is related to the rate of disappearance of bromide ions because bromide ions (Br-) are being oxidized to form bromine (Br2) in the reaction. As the reaction progresses, the concentration of bromide ions decreases, resulting in a decrease in the rate of disappearance of bromide ions. At the same time, the concentration of bromine increases, leading to an increase in the rate of appearance of bromine. Therefore, the rate of appearance of bromine is directly proportional to the rate of disappearance of bromide ions in this reaction.
15.
For the reaction N2O5(g) 2NO2(g) + 1/2O2(g) the value of rate of disappearance of N2O5 is given as 6.25 × 10–3 mol L–1 s–1. The rate of formation of NO2 and O2 is given respectively as:
Correct Answer
A. 1.25 x 10-2 mol L-1 s-1 and 3.125 x 10-3 mol L-1 s-1
Explanation
The rate of formation of NO2 and O2 can be determined by using the stoichiometry of the reaction. From the balanced equation, we can see that for every 1 mole of N2O5 that disappears, 2 moles of NO2 and 1/2 mole of O2 are formed. Therefore, the rate of formation of NO2 is half the rate of disappearance of N2O5, which is 1.25 x 10-2 mol L-1 s-1. Similarly, the rate of formation of O2 is also half the rate of disappearance of N2O5, which is 3.125 x 10-3 mol L-1 s-1.