List of top Questions asked in WBJEE

The number of solutions of log2(x – 1) = 2 log2(x – 3) is

$\sum _{r=0}^{m}n+r{c}_r$ is equal to

The locus of the centre of a circle which passes through two variable points (a, 0), (–a, 0) is 

At temperature 300 K for reaction  C2H4(g) + 3O2(g)→ 2CO2(g) + 2H2O(g); ΔH = −336.2 kcal.  The approximate value of ΔU  at 300 K for the same reaction (R = 2 cal degree^{− 1} mol^{− 1}) will be-

A compound is formed by substitution of two chlorine for two hydrogens in propane. The number of possible isomeric compounds is 

If nt number of radioatoms are present at time t, the following expression will be a constant : 

Ethelene can be separated from acetylene by passing the mixture through : 

Of the following acids the one which has the capability to form complex compound and also possesses oxidizing and reducing properties is:

Out of the 20 amino acids, only two of them contain sulfur. Those two amino acids are:

Atoms in a P4 molecule of white phosphorus are arranged regularly in the following way : 

If $y=2x^3-2x^2+3x-5$, then for $x=2$ and $\mathrm{\Delta }x=0.1$ value of $\mathrm{\Delta }y$ is:

$\mathrm{f}\mathrm{A}+\mathrm{B}+\mathrm{C}=,$ then $\tan \left(\frac{\mathrm{A}}{2}\right)\tan \left(\frac{\mathrm{B}}{2}\right)+\tan \left(\frac{\mathrm{B}}{2}\right)\tan \left(\frac{\mathrm{C}}{2}\right)+\tan \left(\frac{\mathrm{C}}{2}\right)\tan \left(\frac{\mathrm{A}}{2}\right)$ is equal to

The approximate value of 5√33 correct to 4 decimal places is 

The derivative of f(tan x) w.r.t. g(sec x) at x = π/4 where f`(1) = 2 and g`(√2) =4, is

The general solution of the differential equation ${\log }_e\left(\frac{dy}{dx}\right)=x+y$ is

The number of solutions of  2sin x + cos x = 3 is 

If A and B are coefficients of xⁿ in the expansions of (1+ x)2ⁿ and (1+x)^{2n – 1} respectively, then A/B is equal to 

If it is assumed that ${}_{\mathrm{\infty }}^{235}U$ decays only by emitting a and $\beta$ particles, the possible product of the decay is:

The reaction that takes place when Cl2 gas is passed through conc. NaOH solution is : 

Consider the following statements:1. The nuclear fuels uranium-235 and plutonium-239 are the materials from which nuclear weapons are made.2. Radioactive radon gas is a colourless gas produced from the decay of plutonium.Which of the above given statements is/are correct?

Consider the reaction:VO + Fe2O3 → FeO + V2O5Calculate the weight of FeO produced from 2 g of VO and 5.75 g of Fe2O3.[Take atomic weights of V and Fe to be 51 u and 56 u, respectively.]

The variation of pH during the titration of 0.5 N Na2CO3 against 0.5 N HCl is shown in the following graph:

The following table indicates the colour and pH range of different indicators:

Based on the given graph and table, which of the following statements are correct?a. The first point of inflection can be detected by cresolphthalein.b. The complete neutralisation can be detected by bromothymol blue.c. The second point of inflection can be detected by bromocresol red.d. The volume of HCl required for the first point of inflection is half of the volume of HCl required for the second point of inflection.

In the titration of Fe²⁺ ions versus Cr2O7^2– ions using diphenylamine as the internal indicator, phosphoric acid is added in the solution containing Fe²⁺ ions. The role of phosphoric acid is to

In which of the reactions given below does H2PO4^- behave as an acid?(i) $H_{3}P{O}_4+H_{2}O\to H_3{O}^{+}+H_{2}P{O}_4^{-}$(ii) $H_{2}P{O}_4^{-}+H_{2}O\to H_3{O}^{+}+HP{O}_4^{2-}$(iii) $H_{2}P{O}_4^{-}+O{H}^{-}\to H_{3}P{O}_4+O^{2-}$