List of top Questions asked in WBJEE

An optically active alkene having molecular formula C$_8$H$_{16$ gives acetone as one of the products on ozonolysis. The structure of the alkene is}

Compound given below will produce effervescence when mixed with aqueous sodium bicarbonate solution

Consider the gas phase dissociation, PCl$_5$(g) $\rightleftharpoons$ PCl$_3$(g) + Cl$_2$(g) with equilibrium constant $K_p$ at a particular temperature and pressure $P$. The degree of dissociation ($\alpha$) for PCl$_5$(g) is

An egg takes 4.0 minutes to boil at sea level where boiling point of water is $T_1$ K, whereas it takes 8.0 minutes to boil on a mountain top where boiling point of water is $T_2$ K. The activation energy for the reaction that takes place during boiling of egg is

For a chemical reaction, half-life period ($t_{1/2}$) is 10 minutes. How much reactant will be left after 20 minutes if one starts with 100 moles of reactant and the order of the reaction be (i) zero, (ii) one and (iii) two?

$^{10_{5}$B + $^{4}_{2}$He $\rightarrow$ X + $^{1}_{0}$n. In the above nuclear reaction, X will be}

How many oxygen atoms are present in 0.36 g of a drop of water at STP?

The bond order of HeH$^+$ is

360 cm$^3$ of a hydrocarbon diffuses in 30 minutes, while under the same conditions 360 cm$^3$ of SO$_2$ gas diffuses in one hour. The molecular formula of the hydrocarbon is

As per the following equation, 0.217 g of HgO (molecular mass = 217 g mol$^{-1}$) reacts with excess iodide. On titration of the resulting solution, how many mL of 0.01 M HCl is required to reach the equivalence point? \[ \text{HgO} + 4\text{I}^- + \text{H}_2\text{O} \rightarrow \text{HgI}_4^{2-} + 2\text{OH}^- \]

The number of lone pair of electrons and the hybridization of Xenon (Xe) in XeOF$_2$ are

The coagulating power of electrolytes having ions Na$^+$, Al$^{3+$ and Ba$^{2+}$ for As$_2$S$_3$ sol increases in the order}

How many electrons are needed to reduce N$_2$ to NH$_3$?

The common stable oxidation states of Eu and Gd are respectively

Increasing order of solubility of AgCl in (i) H$_2$O, (ii) 1M NaCl (aq.), (iii) 1M CaCl$_2$ (aq.), and (iv) 1M NaNO$_3$ (aq.) solution

Which of the following oxides is paramagnetic?

Which of the following hydrogen bonds is likely to be the weakest?

What is the four-electron reduced form of O$_2$?

Adiabatic free expansion of ideal gas must be

P and Q combine to form two compounds $ PQ_2 $ and $ PQ_3 $. If 1 g $ PQ_2 $ in 51 g benzene gives depression of freezing point $0.8^\circ C$ and 1 g $ PQ_3 $ gives $0.625^\circ C$. ( $K_f = 5.1$ ). Find atomic masses of P and Q.

The number of terminal and bridging hydrogens in $ B_2H_6 $ are respectively

If three elements A, B, C crystallise in a cubic lattice with B at cube centres, C at edge centres and A at corners, the formula of the compound is

An LPG (Liquefied Petroleum Gas) cylinder weighs 15.0 kg when empty. When full, it weighs 30.0 kg and shows a pressure of 3.0 atm. In the course of usage at $27^\circ$C, the mass of the full cylinder is reduced to 24.2 kg. The volume of the used gas in the normal usage condition (1 atm and $27^\circ$C) is (assume LPG to be normal butane and it behaves ideally):

The molar conductances of Ba(OH)$_2$, BaCl$_2$ and NH$_4$Cl at infinite dilution are 523.28, 280.0 and 129.8 S cm$^2$ mol$^{-1$ respectively. The molar conductance of NH$_4$OH at infinite dilution will be:}

A wave disturbance in a medium is described by \[ y(x,t)=0.02\cos\left(50\pi t + \frac{\pi}{2}\right)\cos(10\pi x), \] where $ x,y $ are in meters and $ t $ in seconds. Which statements are correct?