List of top Chemistry Questions asked in JEE Main

The total number of amines among the following which can be synthesized by Gabriel synthesis is _________. (A) ethylamine, (B) n-propylamine, (C) benzylamine, (D) aniline
1.86 g of aniline completely reacts to form acetanilide. 10% of the product is lost during purification. Amount of acetanilide obtained after purification (in g) is _________ × 10−2.
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Heavy water is used for the study of reaction mechanism.
Reason (R): The rate of reaction for the cleavage of O-H bond is slower than that of O-D bond.

The reaction rate for the reaction 

where square brackets are used to denote molar concentrations. The equilibrium constant K\(_c\) = __________ . (Nearest integer)} 
 

The following data was obtained for chemical reaction given below at 975 K: 

The order of the reaction with respect to NO is _________. (Integer answer) 
 

The reaction that occurs in a breath analyser, a device used to determine the alcohol level in a person's blood stream is:
\(2 K_2Cr_2O_7 + 8 H_2SO_4 + 3 C_2H_6O \to 2 Cr_2(SO_4)_3 + 3 C_2H_4O_2 + 2 K_2SO_4 + 11 H_2O\)
If the rate of appearance of \(Cr_2(SO_4)_3\) is \(2.67 \, \text{mol min}^{-1}\) at a particular time, the rate of disappearance of \(C_2H_6O\) at the same time is _________ \(\text{mol min}^{-1}\). (Nearest integer)
The first order rate constant for the decomposition of CaCO\(_3\) at 700 K is 6.36 \(\times\) 10\(^{-3}\) s\(^{-1}\) and activation energy is 209 kJ mol\(^{-1}\). Its rate constant (in s\(^{-1}\)) at 600 K is \(x \times 10^{-6}\). The value of x is _________. (Nearest integer)
[Given R = 8.31 J K\(^{-1}\) mol\(^{-1}\); log 6.36\(\times\)10\(^{-3}\)=\(-2.19\), 10\(^{-4.79}\)=1.62\(\times\)10\(^{-5}\)]

According to the following figure, the magnitude of the enthalpy change of the reaction \(A + B \to M + N\) in kJ mol\(^{-1}\) is equal to \(\dots\dots\dots\). (Integer answer) 
[Given: \(x = 20\text{ kJ mol}^{-1}\), \(y = 45\text{ kJ mol}^{-1}\), \(z = 15\text{ kJ mol}^{-1}\)] 

For a first order reaction, the ratio of the time for \(75%\) completion of a reaction to the time for \(50%\) completion is \(\dots\dots\dots\). (Integer answer)
For the reaction $\text{A} \to \text{B}$, the rate constant $k$ (in $\text{s}^{-1}$) is given by $\log_{10} k = 20.35 - \frac{2.47 \times 10^3}{\text{T}}$. The energy of activation in $\text{kJ mol}^{-1}$ is ________. (Nearest integer) [Given : R = 8.314 J K$^{-1}$ mol$^{-1}$]
The rate constant of a reaction increases by five times on increase in temperature from 27°C to 52°C. The value of activation energy in kJ mol⁻¹ is ________. (Rounded-off to the nearest integer) [R=8.314 JK⁻¹ mol⁻¹]
For a reaction of order n, the unit of the rate constant is :

For aA + bB $\rightarrow$ cC + dD, the plot of log k vs 1/T is given below :

The temperature at which the rate constant is $10^{-4}$ s$^{-1}$ is __________ K. [Rate constant is $10^{-5}$ s$^{-1}$ at 500 K.]

Gaseous cyclobutene isomerizes to butadiene in a first order process which has a 'k' value of $3.3 \times 10^{-4} s^{-1}$ at 153°C. The time in minutes it takes for the isomerization to proceed 40% to completion at this temperature is __________. (Rounded off to the nearest integer)
A reaction has a half life of 1 min. The time required for 99.9% completion of the reaction is ________ min. (Round off to the Nearest Integer). [Use : ln 2 = 0.69; ln 10 = 2.3]
For the first order reaction $A \rightarrow 2B$, 1 mole of reactant A gives 0.2 moles of B after 100 minutes. The half life of the reaction is ________ min. (Round off to the Nearest Integer).

For the following graphs, 

Choose from the options given below, the correct one regarding order of reaction : 
 

The overall order of the reaction is _________. (Round off to the Nearest Integer) based on the NO and Cl$_2$ data.
Sucrose hydrolyses in acid solution into glucose and fructose following first order rate law with a half-life of 3.33 h at 25 °C. After 9 h, the fraction of sucrose remaining is \( f \). The value of \( \log_{10}(1/f) \) is _______ × 10−2. (Rounded off to the nearest integer)
For the galvanic cell,
Zn(s) + Cu\(^{2+}\) (0.02 M) \(\rightarrow\) Zn\(^{2+}\) (0.04 M) + Cu(s),
E\(_{cell}\) = __________ \(\times\) 10\(^{-2}\) V. (Nearest integer)
[Use : E\(^0_{Cu/Cu^{2+}}\) = -0.34 V, E\(^0_{Zn/Zn^{2+}}\) = +0.76 V, \(\frac{2.303 RT}{F} = 0.059V\)]
Given below are two statements :
Statement I : The limiting molar conductivity of KCl (strong electrolyte) is higher compared to that of \(CH_3COOH\) (weak electrolyte).
Statement II : Molar conductivity decreases with decrease in concentration of electrolyte.
In the light of the above statements, choose the most appropriate answer from the options given below :
These are physical properties of an element
(A) Sublimation enthalpy
(B) Ionisation enthalpy
(C) Hydration enthalpy
(D) Electron gain enthalpy
The total number of above properties that affect the reduction potential is _________. (Integer answer)
The resistance of a conductivity cell with cell constant 1.14 cm\(^{-1}\), containing 0.001 M KCl at 298 K is 1500 \(\Omega\). The molar conductivity of 0.001 M KCl solution at 298 K in S cm\(^2\) mol\(^{-1}\) is _________. (Integer answer)
Consider the following cell reaction
\(\text{Cd}_{(s)} + \text{Hg}_2\text{SO}_{4(s)} + \frac{9}{5} \text{H}_2\text{O}_{(l)} \rightleftharpoons \text{CdSO}_4 \cdot \frac{9}{5} \text{H}_2\text{O}_{(s)} + 2\text{Hg}_{(l)}\)
The value of \(E_{cell}^0\) is \(4.315\text{ V}\) at \(25^\circ\text{C}\). If \(\Delta H^0 = -825.2\text{ kJ mol}^{-1}\), the standard entropy change \(\Delta S^0\) in J K\(^{-1}\) is \(\dots\dots\dots\). (Nearest integer)
[Given : Faraday constant = \(96487\text{ C mol}^{-1}\)]
Match List - I with List - II :
\[ \begin{array}{llcl} & \text{List - I} & & \text{List - II} \\ \text{(Parameter)} & & \text{(Unit)} \\ (a) & \text{Cell constant} & (i) & \text{S cm}^2 \text{ mol}^{-1} \\ (b) & \text{Molar conductivity} & (ii) & \text{Dimensionless} \\ (c) & \text{Conductivity} & (iii) & \text{m}^{-1} \\ (d) & \text{Degree of dissociation of electrolyte} & (iv) & \Omega^{-1} \text{m}^{-1} \\ \end{array} \]
Choose the most appropriate answer from the options given below :