List of top Chemistry Questions asked in JEE Main

20 g Zn is treated with 50 ml, 50% (w/w) $ \mathrm{H_2SO_4} $ solution $(d = 1.3 \, \mathrm{g/ml})$. The volume of $ \mathrm{H_2} $ gas evolved at STP is:

Determine the order of molar heat capacity $ \left(C_m\right) $ of $ \mathrm{Br_2(\ell) $, $ \mathrm{Cu(s)} $ and $ \mathrm{He(g)} $ at $ 298 \, \mathrm{K} $ and $ 1 \, \mathrm{atm} $.

For the reaction:
\[ \text{A(g)} \rightleftharpoons \text{B(g)} + \text{C(g)} \] Initial moles of A(g) is $a$. At equilibrium, $x$ moles of A decompose at total pressure $P$. Calculate $K_P$ for the given reaction.

In 1 litre aqueous solution 20 g of Haemoglobin is present at 300 K. This solution has height difference of 80 mm, when separated from pure water through S.P.M. If density of solution is 1000 kg/m$^3$, then calculate molar mass of Haemoglobin in kg/mol. (Use : $g = 10$ m/s$^2$)

In a period, ionisation energy of the extreme left and electronegativity of the extreme right element is respectively ______. (Don’t consider Noble gases).

Given below are two statements:

0.2 g of an organic compound is subjected to estimation of $S$ by Carius method, giving $0.6$ g $BaSO_4$. Find \% of $S$. (Nearest integer)

Compare the bond length x, y, and z in the following compound.

The compound

is treated sequentially with: (A) Excess HI/Red P
(B) $ \text{V}_2\text{O}_5 $, 773 K
(C) Benzyl chloride/AlCl$_3$
Find the number of π-bonds in the final product.

Given the nuclear reaction: \[ \text{H}_2^2 + \text{H}_1^2 \rightarrow \text{He}_4 \] Binding energy per nucleon of H$_1^2$ and H$_2^4$ are 1.1 MeV and 7 MeV respectively. Find energy released in the nuclear reaction given above.

The hybridisation states of Ni in the 3 complexes Ni(CO)$_4$, [Ni(NH$_3$)$_6$]$^{2+}$, [Ni(CN)$_4$]$^{2-}$ are

For tetrahedral complex, the correct order of energy of $d$-orbitals is:

Match the following:

Consider the reaction:

Find the number of moles of benzene formed if the efficiency of reaction is 60%.

Sucrose hydrolyses in acidic medium to form glucose and fructose which follows first order kinetics. If the half-life of sucrose is 3 hrs, find the % of sucrose left after 6 hrs.

Select the correct statements : (a) Glucose has 2 anomeric forms.
(b) Both forms have difference in configuration at $C_1$ carbon.
(c) $\alpha$-form has more melting point than $\beta$-form.
(d) Specific rotation of $\alpha$-form is $+19^\circ$ and $\beta$-form has $+112^\circ$.
(e) $\alpha$-form crystallises at $307^\circ$ and $\beta$-form crystallises at $371^\circ$.

An ideal gas is placed in a container at $ (P_1, V_1, T_1) $ and another ideal gas is placed in a different container at $ (P_2, V_2, T_2) $ are mixed at final pressure of $ P $ and final volume of $ V $. Calculate the final temperature.

Calculate the number of molecules and moles of $ \text{SO_2 $ in its 1.479 liters at STP.}

(A) Bond angle Cr–O–Cr in $ \text{CrO}_7^{2-} $ is 126° (B) $ \text{Na}_2\text{Cr}_2\text{O}_7 $ is used as primary standard solution in titration. (C) $ \text{K}_2\text{Cr}_2\text{O}_7 $ oxidises $ \text{Fe}^{2+} $ into $ \text{Fe}^{3+} $ in acidic medium. (D) $ \text{CrO}_4^{2-} $ and $ \text{Cr}_2\text{O}_7^{2-} $ are interconvertible by changing pH.

IUPAC Name of the formed compound:

Match the column:

} Match correct reagents with given reactions:

Statement-1: Heat capacity at constant volume is always greater than heat capacity at constant pressure.
Statement-2: At constant volume as work done is zero, heat given to the chaotic motion is reflected by increase in temperature.

Arrange the following groups according to their decreasing order of electron withdrawing nature – $ \text{COOH} $, $ \text{CN} $, $ I $, and $ \text{NO}_2 $.

The reaction follows 1st order reaction $ \text{R} \rightarrow \text{P} $ Find the fraction of molecules dissociated in time $ t $. $[k_1 = \text{Rate constant}]$

Anion $ X^- $ contains 45 neutrons and 36 electrons. The atomic mass, period number, and state in which "X" exists is: