GUJCET Chemical Kinetics — practice questions
81 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice GUJCET Chemical Kinetics in the app →The SI/CGS-style units of the **rate of a chemical reaction** are:For the reaction A → B, the rate of reaction can be written as:The **order of a reaction** is defined as:The **rate constant** $k$ in a rate law equals the rate of reaction when:The order of a reaction:For a zero-order reaction, the units of the rate constant $k$ are:For a first-order reaction, the units of the rate constant $k$ are:**Molecularity** of an elementary reaction refers to:The **instantaneous rate** of a reaction at time $t$ is obtained from a concentration–time graph as:For the reaction $aA + bB \to cC + dD$, the rate in terms of stoichiometric coefficients is:For the reaction $2N_2O_5(g) \to 4NO_2(g) + O_2(g)$, if $N_2O_5$ disappears at 0.02 mol dm⁻³ s⁻¹, the **rate oFor the same reaction ($2N_2O_5 \to 4NO_2 + O_2$, $d[N_2O_5]/dt = -0.02$), the **rate of formation of $NO_2$**For the reaction A + B → P, doubling [A] (at constant [B]) doubles the rate; doubling [B] (at constant [A]) quFor the reaction $2\text{NOBr}(g) \to 2\text{NO}_2(g) + \text{Br}_2(g)$, rate = $k[\text{NOBr}]^2$. If rate = If rate = $k[A][B]^2$, what are the units of $k$?For the reaction A + B → P, doubling [A] doubles the rate; tripling [A] **and** doubling [B] multiplies the raFor the reaction $2A + B \to$ products, the rate law is rate = $k[A]^2[B]$. If [A] is **tripled** and [B] is uFor the reaction $2A + B \to 2C + D$, rate = $6 \times 10^{-4}$ mol dm⁻³ s⁻¹ at $[A] = [B] = 0.3$ M. If the reFor the reaction A + B → P with rate law rate = $k[A]^2[B]$, $k = 6.25$ M⁻² s⁻¹ at 25 °C. The rate when $[A] =The rate of a reaction at 27 °C is $k$. The temperature is increased to 37 °C. Assuming the standard rule thatWhich of the following statements about **order vs molecularity** is correct?The reaction $CHCl_3(g) + Cl_2(g) \to CCl_4(g) + HCl(g)$ is first order in $CHCl_3$ and one-half order in $Cl_For the reaction A + B → P, the following initial-rate data were obtained:
| [A]/M | [B]/M | Initial rate (M/For the reaction A + B → P with $\text{rate} = k[A][B]^2$, rate = $3.6 \times 10^{-2}$ mol dm⁻³ s⁻¹ when [A] =For the reaction $2NO(g) + 2H_2(g) \to N_2(g) + 2H_2O(g)$, rate = $k[NO]^2[H_2]$. The orders w.r.t. NO, $H_2$,A first-order reaction completes 75% in 30 minutes. Its half-life (using $t_{1/2}$ being independent of concenFor the reaction $3I^-(aq) + S_2O_8^{2-}(aq) \to I_3^-(aq) + 2SO_4^{2-}(aq)$, if the rate of formation of $SO_Consider $2A + 2B \to 2C + D$. Doubling [A] at constant [B] quadruples the rate; doubling [B] at constant [A] For a zero-order reaction $A \to P$, the integrated rate law is $[A]_t = [A]_0 - kt$. If initial $[A]_0 = 1.0$For a first-order reaction, the relation between rate constant and half-life is $t_{1/2} = 0.693/k$. If $k = 2Chemical kinetics is the branch of chemistry that deals with:For the reaction R → P, the *instantaneous* rate of reaction is given by:For the reaction 2HI(g) → H₂(g) + I₂(g), the rate of reaction is:For 5Br⁻(aq) + BrO₃⁻(aq) + 6H⁺(aq) → 3Br₂(aq) + 3H₂O(l), the rate of reaction can be expressed as:The SI unit of rate of a reaction is:The rate law for a reaction must be:The order of a reaction is defined as:The units of the rate constant k for a zero-order reaction are:The units of the rate constant k for a first-order reaction are:A rate constant has units of L mol⁻¹ s⁻¹. The order of the reaction is:Molecularity of a reaction is best defined as:Reactions with molecularity higher than 3 are very rare because:For a zero-order reaction R → P, the integrated rate equation is:For a first-order reaction, the half-life t_(1/2) is:All radioactive decays follow which order of kinetics?A first-order reaction with rate constant k = 5.5 × 10⁻¹⁴ s⁻¹ has a half-life of approximately:Hydrolysis of an ester (e.g., ethyl acetate) in dilute aqueous solution behaves as a first-order reaction evenFor a chemical reaction, with a rise in temperature by 10°C, the rate of reaction typically:The Arrhenius equation is:In the Arrhenius equation k = A e^(−E_a/RT), the term e^(−E_a/RT) represents:On a plot of ln k versus 1/T (Arrhenius plot), what is the slope?A catalyst speeds up a reaction by:In the Arrhenius equation, the pre-exponential factor A is also called:The activation energy of a reaction is best described as:For a first-order reaction, the time required for 99.9% completion is approximately:For a first-order reaction, if the initial concentration of N₂O₅ is 1.24 × 10⁻² mol L⁻¹ and after 60 min it isFor a zero-order reaction, if the initial concentration is doubled, the half-life:Time required to decompose SO₂Cl₂ to half of its initial amount is 60 min. Assuming first-order kinetics, the Rate of reaction is defined as:Rate law: r = k [A]ᵐ [B]ⁿ. Sum m + n is called:For a first-order reaction, rate ∝:Units of rate constant k for a first-order reaction:Arrhenius equation: k = A × e^(-Ea/RT). What is A?For first-order reaction, half-life t₁/₂:For zero-order reaction A → P, rate equals:For first-order, integrated rate law:For second-order reaction (single reactant), integrated rate law:Temperature dependence: per Arrhenius, raising T from 300 K to 310 K (Ea = 50 kJ/mol) increases k by approximaCatalyst affects:Order of reaction CAN be determined from:A first-order reaction is 25% complete in 20 min. Time for 75% completion:For a reaction with Ea = 100 kJ/mol, find k₂/k₁ when T goes from 300 K to 350 K. (R = 8.314 J/mol K):For a 2nd-order reaction with [A]₀ = 0.5 M and k = 0.1 L mol⁻¹ s⁻¹, half-life:For complex reaction with rate-determining step that involves 2 molecules of A, the order in A is:For Arrhenius plot of ln k vs 1/T, slope equals:Threshold energy = Ea + average kinetic energy of reactants. If Ea = 50 kJ/mol and avg KE = 4 kJ/mol, thresholFor reaction A → B with rate constant 10⁻³ s⁻¹ (first order), concentration after 1000 s if [A]₀ = 1 M:A reaction has k = 0.05 s⁻¹. After how many seconds is 90% complete?For radioactive decay (1st order), if 1/8 of initial nuclei remain, how many half-lives elapsed?A catalyst lowers Ea from 100 kJ/mol to 75 kJ/mol at T = 300 K. Rate enhancement factor (R = 8.314 J/mol K):For elementary bimolecular reaction 2 NO → products, rate law is: