List of top Chemistry Questions asked in JEE Main

Match the column-I with column-II:

Choose the correct match.

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.

(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.

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

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

Match the column:

} Match correct reagents with given reactions:

Consider the following reaction:

What is the colour of the final compound B?

Soluble in aqueous NaOH

Statement-1: Under certain conditions, the covalency of oxygen can be up to 4. In \( \text{SO}_2 \), the oxidation state of oxygen is \( -2 \) and in \( \text{OF}_2 \), the oxidation state of oxygen is \( +2 \). Statement-2: The anomalous behaviour of oxygen in the 16th group is due to its small size and high electronegativity.

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

For the reaction
\[ \text{A} + \text{B} \rightleftharpoons \text{C}, \quad K_p = 2.7 \times 10^{-5} \] Calculate \( K_p \) for the reaction
\[ \frac{1}{3} \text{A} + \frac{1}{3} \text{B} \rightleftharpoons \frac{1}{3} \text{C} \]

Choose the correct match.

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

For process \( X \to Y \), work done by the gas is 10 J and heat absorbed in the process is 2 J. For the reverse process, heat evolved is 6 J. Find the work done for the reverse process.

How many of the following are paramagnetic:
Lu\(^{3+}\), Yb\(^{2+}\), Gd\(^{2+}\), Ce\(^{4+}\), La\(^{3+}\), Zn\(^{2+}\), Cu\(^{2+}\), Mn\(^{2+}\), Sc\(^{3+}\), and Ti\(^{4+}\)

Identify correct statement(s):
(i) \( \text{Ar–Cl} \) and \( \text{R–Cl} \) show similar chemical properties.
(ii) Rate of \( S_N^1 \) \( C_6H_5CH_2–Cl<C_6H_5–CH–C_6H_5 \)
(iii) Alcohol is more polar than water, so alcoholic KOH shows elimination reaction.
(iv) Vinyl alcohol is an alkene, whereas allyl alcohol is an alkyne.
(v) Alcohol with SOC\(_2\) gives alkyl halide, but phenol does not give.

"X" is an oxoanion of the lightest element of group 7 (in the periodic table). The metal is in +6 oxidation state in "X". The color of the potassium salt of X is

Given below are two statements: Statement I: Glucose is found to exist in two different anomeric forms \(\alpha\) and \(\beta\). Statement II: In open chain structure, \(C_2, C_3, C_4\) of glucose and fructose both have same orientation. In light of above statements choose the correct option.

Consider the following equilibrium: \[ 2AB \rightleftharpoons A_2 + B_2 \] If equilibrium pressure is \(P\) and degree of dissociation is \(\alpha\), then \(K_p\) is

Consider the following electrochemical cell \[ Zn | Zn^{2+}(aq) \, || \, Ag^{+}(aq) | Ag \] \[ [Zn^{2+}] = 1\,M \] The \(E_{cell\) was found to be \(1.6\,V\). The value of \(\log[Ag^+]\) is \[ E^\circ_{Zn^{2+}/Zn} = -0.76\,V , \qquad E^\circ_{Ag^+/Ag} = +0.80\,V \]

The order of acidic strength in the following compounds is A. Phenol
B. p-nitrophenol
C. Ethanol
D. p-methoxyphenol

Given below are two statements: Statement I: The shape of \(ICl_3^{-}\) is square planar. Statement II: The shape of \(ClBr_2^{-}\) is pyramidal. In light of above statements choose the correct option.

Which compound has total molecular mass of 72 with three primary carbons?

On heating \(2.76\,\text{g}\) of \( \text{Ag}_2\text{CO}_3 (s) \), some solid residue is left behind. Determine the mass of residue left.