Methods for Ester Synthesis

Q. For a reaction, $A+B\to$ product the rate law is given by, $r=k\left[A{]}^{1/2}\right[B{]}^2$. What is the order of the reaction ?

Q. The decomposition of $N_2{O}_5$ in $CC{l}_4$ at 318 $K$ has been studied by monitoring the concentration of $N_2{O}_5$ in the solution. Initially the concentration of $N_2{O}_5$ is $2.33(mol{L}^{-1}$ and after $184$ minutes, it is reduced to $2.08mol{L}^{-1}$. The reaction takes place according to the equation

$2N_2{O}_5\left(g\right)\to 4N{O}_2\left(g\right)+O_2\left(g\right)$

Calculate the average rate of this reaction in terms of hours, minutes and seconds. What is the rate of production of $N{O}_2$ during this period?

Q. $AandB$ decompose via first order kinetics with half-lives $54.0minand18.0min$ respectively. Starting from an equimolar non reactive mixture of $AandB$, the time taken for the concentration of $A$ to become $16times$ that of $B$ is _________ min.
(Round off to the Nearest Integer) Take $\ln 2=0.693$.

Q. The rate constants of a reaction at $500k\text{and}700k\text{are}0.02s^{=1}$ and $0.07s^{-1}$ respectively. Calculate the values of $E_a$ and $A$.

Q. The forward and backward activation energy of exothermic reaction $A\to B$ is $80$ and $280{\text{kJ mol}}^{-1}$ respectively. The enthalpy change of the forward reaction $A\to B\left({\text{in kJ mol}}^{-1}\right)$ will be:

1. $-80$
2. $-200$
3. $-280$
4. $-360$

Q. The following concentrations were obtained for the formation of $N{H}_3$ from $N_2\text{and}{N}_2$ at equilibrium at $500K$. $\left[N_2\right]=1.5\times {10}^{-2}M$. $\left[H_2\right]=3.0\times {10}^{-2}M$ and $\left[N{H}_3\right]=1.2\times {10}^{-2}M$. Calculate equilibrium constant.

Q. Permanganate$\left(VII\right)$ ion, $Mn{O}_4^{-}$ in basic solution oxidises iodide ion, $I^{–}$ to produce molecular iodine $\left(I_2\right)$ and manganese $\left(IV\right)$ oxide $\left(Mn{O}_2\right)$. Write a balanced ionic equation to represent this redox reaction.

Q. The following data were obtained during the first order thermal decomposition of $N_2{O}_5\left(g\right)$ at constant volume :
$2N_2{O}_5\left(g\right)\to 2N_2{O}_4\left(g\right)+O_2\left(g\right)$

$\begin{array}{ccc}\text{S.NO}& \text{Time/s}& \text{Total Pressure/(atm)}\\ 1& 0& 0.5\\ 2& 100& 0.512\end{array}$

Calculate the rate constant.

Q. Time required to decompose $S{O}_{2}C{l}_2$ to half of its initial amount is $60$ minutes. If the decomposition is a first order reaction, calculate the rate constant of the reaction.

Q. Rate law for the reaction $A+2B\to C$ is found to be 𝑅𝑎𝑡𝑒 $=k\left[A\right]\left[B\right]$Concentration of reactant ‘B’ is doubled, keeping the concentration of ‘A’ constant, the value of rate constant will be______.

1. the same
2. quadrupled
3. halved
4. doubled

Q.

Assertion: Order and molecularity are the same.

Reason: Order is determined experimentally, and molecularity is the sum of the stoichiometric coefficients of the rate-determining elementary step.

1. Assertion is correct but reason is incorrect.

2. Assertion is incorrect but reason is correct.

3. Both assertion and reason are correct but reason does not explain assertion.

4. Both assertion and reason are correct and the reason is correct explanation of assertion.

5. Both assertion and reason are incorrect.

Q. The rate constant of a reaction is 1.2*10-2 mol-2L2 s-1. The order of the reaction is

Q. Balance the following ionic equation:

A) $C{r}_2{O}_7^{2-}+H^{+}+I^{-}\to C{r}^{3+}+I_2+H_{2}O$

B) $C{r}_2{O}_7^{2-}+F{e}^{2+}+H^{+}\to C{r}^{3+}+F{e}^{3+}+H_{2}O$

C) $Mn{O}_4^{-}+S{O}_3^{2-}+H+\to M{n}^{2+}+S{O}_4^{2-}+H_{2}O$

D) $Mn{O}_4^{-}+H^{+}+B{r}^{-}\to M{n}^{2+}+B{r}_2+H_{2}O$

Q. Identify the reaction order from each of the following rate constants.
A).$k=2.3\times {10}^{-5}Lmo{l}^{-1}{s}^{-1}$.

B).$k=3\times {10}^{-4}{s}^{-1}$

Q. The value of $K_c$ for the reaction $2A\rightleftharpoons B+C$ is $2\times {10}^{-3}$.
At a given time, the composition of reaction mixture is $\left[A\right]=\left[B\right]=\left[C\right]=3\times {10}^{-4}M$.
In which direction the reaction will proceed?

Q. For the reaction $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$, the standard free energy is $\Delta G^{\circ }>0$. The equilibrium constant $\left(K\right)$ would be

1. $K=1$
2. $K>1$
3. $K<1$
4. $K=0$

Q.

Which of the following chemical equations is an unbalanced one?

1. $2{\mathrm{NaHCO}}_3\to {\mathrm{Na}}_2{\mathrm{CO}}_3+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

2. $2{\mathrm{C}}_4{\mathrm{H}}_{10}+12{\mathrm{O}}_2\to 8{\mathrm{CO}}_2+10{\mathrm{H}}_2\mathrm{O}$

3. $2\mathrm{Al}+6{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{Al}{\left(\mathrm{OH}\right)}_3+3{\mathrm{H}}_2$

4. $4{\mathrm{NH}}_3+5{\mathrm{O}}_2\to 4\mathrm{NO}+6{\mathrm{H}}_2\mathrm{O}$

Q. Activation energy $\left(E_a\right)$ and rate constant $\left(k_1\right)$ and $\left(k_2\right)$ of a chemical reaction at two different temperatures $\left(T_1\right)$ and $\left(T_2\right)$ are related by -

1. $ln\frac{k_2}{k_1}=\frac{E_a}{R}(\frac{1}{T_1}-\frac{1}{T_2})$​
2. $ln\frac{k_2}{k_1}=-\frac{E_a}{R}(\frac{1}{T_1}-\frac{1}{T_2})$​
3. $ln\frac{k_2}{k_1}=\frac{E_a}{R}(\frac{1}{T_1}+\frac{1}{T_2})$​
4. $ln\frac{k_2}{k_1}=\frac{R}{E_a}(\frac{1}{T_1}+\frac{1}{T_2})$​

Q.

76. Sucrose doesn’t respond to Tollen’s test. But it gives a positive result after boiling with conc. $\mathrm{HCl}$. It is due to the

1. cleavage of glycosidic linkage

2. formation of glycosidic linkage

3. formation of a compound containing carboxylic acid group

4. isomerisation to glucose units

Q. $K_{a_1},K_{a_2}$ and $K_{a_3}$ are respective ionization constants for the following reactions.

$H_{2}S\rightleftharpoons H^{+}+H{S}^{-}$

$H{S}^{-}\rightleftharpoons H^{+}+S^{2-}$

$H_{2}S\rightleftharpoons 2H^{+}+S^{2-}$

The correct relationship between $K_{a_1},K_{a_2}$ and $K_{a_3}$ is

1. $K_{a_3}=K_{a_1}-K_{a_2}$
2. $K_{a_3}=K_{a_1}/K_{a_2}$
3. $K_{a_3}=K_{a_1}+K_{a_2}$
4. $K_{a_3}=K_{a_1}\times K_{a_2}$

Q.

The rate of esterification of alcohols is more for:

1. (CH₃)₃COH

2. C₂H₅OH

3. CH₃OH

4. (CH₃)₂CHOH

Q. $N_2{O}_5\left(g\right)\to 2N{O}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$

In the above first order reaction the initial concentration of $N_2{O}_5$ is 2.40 $\times {10}^{-2}mol{L}^{-1}$ at 318 K. The concentration of $N_2{O}_5$ after 1 hour was $1.60\times {10}^{-2}mol{L}^{-1}$ . The rate constant of the reaction at 318 k is $x\times {10}^{-3}mi{n}^{-1}$ The value of x (Nearest integer) is

$[Given:log3=0.447,log5=0.699]$

Q.

Which of the following statements are in accordance with the Arrhenius equation?

1. Rate of a reaction increases with decrease in activation energy.

2. Rate constant decreases exponentially with increase in temperature.

3. Rate of a reaction increases with increase in temperature.

4. Rate of reaction decreases with decrease in activation energy.

Q.

Using the data given below find out the strongest reducing agent.

$E_{C{r}_2{O}_7^{2-}/C{r}^{3+}}^{\Theta }=1.33V$

$E_{C{l}_2/Cl}^{\Theta }=1.36V$

$E_{Mn{O}_4^{-}/M{n}^{2+}}^{\Theta }=1.51V$

$E_{C{r}^{3+}/Cr}^{\Theta }=-0.74V$

1. $M{n}^{2+}$
2. $Cr$
3. $C{r}^{3+}$
4. $C{l}^{-}$

Q. Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): It is difficult to replace chlorine by $-OH$ in chlorobenzene in companion to that in chloroethane.
Reason (R): chlorine carbon $(C-Cl)$ bond in chlorobenzene has a partial double bond character due to resonance.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true

Q.

Match the items of Column $I$ and Column $II.$

	Column I		Column II
A	Mathematical expression for the rate of a reaction	(i)	rate constant
B	Rate of the reaction for a zero-order reaction is equal to	(ii)	rate law
C	Units of rate constant for a zero-order reaction is the same as that of	(iii)	order of the slowest step
D	Oredr of a complex reaction is determine by	(iv)	rate of a reaction

Q.

In a reaction if the concentration of reactant $A$ is tripled, the rate of reaction becomes twenty seven times. What is the order of the reaction?

Q.

Give the balanced chemical equation for the reaction in which, on being heated with chlorine(${\mathrm{Cl}}_2$), iron($\mathrm{Fe}$) forms iron(III) chloride?

Q.

Assertion: The order of a reaction can be zero or fractional.

Reason: We cannot determine the order from a balanced chemical equation.

Q.

Balance the following equations:

${\mathrm{As}}_2{\mathrm{O}}_3+{\mathrm{H}}_2\mathrm{S}\to {\mathrm{As}}_2{\mathrm{S}}_3+{\mathrm{H}}_2\mathrm{O}$