List of top Questions asked in JEE Main

In Wilkinson?s catalyst, the hybridization of central metal ion and its shape are respectively :

The number of $P - O$ bonds in $P_4O_6$ is :

Two moles of an ideal monoatomic gas occupies a volume $V$ at $27^{\circ}C$. The gas expands adiabatically to a volume $2V$. Calculate $(a)$ the final temperature of the gas and $(b) $ change in its internal energy -

According to molecular orbital theory, which of the following will not be a viable molecule ?

In the given circuit, the current through zener diode is :

Let N denote the set of all natural numbers. Define two binary relations on N as $R_1 = \{(x, y) \epsilon N \times N : 2x + y = 10 \}$ and $R_2 = \{(x, y) \epsilon N \times N : x + 2y = 10 \}$. Then :

$N_2O_5$ decomposes to $NO_2$ and $O_2$ and follows first order kinetics. After $50$ minutes, the pressure inside the vessel increases from $50\, mm\, Hg$ to $87.5\, mm\, Hg.$ The pressure of the gaseous mixture after $100$ minute at constant temperature will be :

Two sitar strings, $A$ and $B$, playing the note ??ha??are slightly out of tune and produce beats of frequency $5\, Hz$. The tension of the string $B$ is slightly increased and the beat frequency is found to decrease by $3\, Hz$. If the frequency of $A$ is $425\, Hz$, the original frequency of $B$ is :

For a positive integer $n$, if the mean of the binomial coefficients in the expansion of $(a + b)^{2n - 3}$ is 16, then $n$ is equal to :

In which of the following reactions, an increase in the volume of the container will favour the formation of products ?

Which of the following conversions involves change in both shape and hybridisation?

Which of the following is a Lewis acid?

The INCORRECT statement is :

Fill in the blanks. (i) If $x > y$ and $z < 0$, then $-xz$ $-yz$. (ii) If $p > 0$ and $q < 0$, then $p - q$ $p$. (iii) If $-2x + 1 \ge 9$, then $x$ $-4$.

The carrier frequency of a transmitter is provided by a tank circuit of a coil of inductance $ 49\,\mu H$ and a capacitance of $2.5 \,nF$. It is modulated by an audio signal of $12 \,kHz$. The frequency range occupied by the side bands is:

Biochemical Oxygen Demand (BOD) value can be a measure of water pollution caused by the organic matter. Which of the following statements is correct ?

Which of the following are Lewis acids ?

The least positive integer n for which $\left( \frac{1 + i \sqrt{3}}{1 - i \sqrt{3}} \right)^n = 1 $, is :

A body takes $10$ minutes to cool from $60^{\circ}C$ to $50^{\circ}C$. The temperature of surroundings is constant at $25^{\circ}C$. Then, the temperature of the body after next $10$ minutes will be approximately :

A carrier wave of peak voltage $14\, V$ is used for transmitting a message signal. The peak voltage of modulating signal given to achieve a modulation index of $80\%$ will be:

The increasing order of the acidity of the following carboxylic acids is :

Xenon hexafluoride on partial hydrolysis produces compounds ?X? and ?Y?. Compounds ?X? and ?Y? and the oxidation state of Xe are respectively :

For a first order reaction, $A \to P, t_{1/2}$ (half life) is 10 days. The time required for $\frac{1^{th}}{4}$ conversion of A (in days) is : (ln 2=0.693, ln 3=1.1)

At a certain temperature in a 5 L vessel, 2 moles of carbon monoxide and 3 moles of chlorine were allowed to reach equilibrium according to the reaction,$CO + Cl_{2} <=> COCl_2 $ At equilibrium, if one mole of CO is present then equilibrium constant $(K_c)$ for the reaction is :

An aqueous solution contains $0.10 \, M \, H_2S$ and $0.20 \, M \, HCl$ . If the equilibrium constants for the formation of $HS^-$ from $H_2S$ is $1.0 \times 10^{-7}$ and that of $S^{2- }$ from $HS^-$ ions is $ 1.2 \times 10^{-13}$ then the concentration of $S^{2-}$ ions in aqueous solution is -