WB JEE 2021

The product(s) in the following sequence of reactions will be

The compounds A and B above are respectively.

The products X and Y which are formed in the following sequence of reactions are respectively.

The atomic masses of helium and neon are 4.0 and 20.0 amu respectively. The value of the de-Broglie wavelength of helium gas at \(-\)73\(^\circ\)C is M times the de-Broglie wavelength of neon at 727\(^\circ\)C. The value of M is

The exact order of acidity of the compounds p-nitrophenol, acetic acid, acetylene and ethanol is

The dipeptides which may be obtained from the amino acids glycine, and alanine are

The H3O+ ions has the following shape

The equilibrium constant for the reaction N2(g) + O2(g) \(\rightleftharpoons\) 2NO(g) is 4 \(\times\) 10\(-\)4 at 2000 K. In presence of a catalyst the equilibrium is attained 10 times faster. Therefore, the equilibrium constant, in presenc...

Under the same reaction conditions, initial concentration of 1.386 mol dm\(-\)3 of a substance becomes half in 40 s and 20 s through first-order and zero-order kinetics respectively. Ratio \(\left( {{{{k_1}} \over {{k_0}}}} \right)\) of the...

2.5 mL 0.4 M weak monoacidic base (Kb = 1 \(\times\) 10\(-\)12 at 25\(^\circ\)C) is titrated with 2/15 M HCl in water at 25\(^\circ\)C. The concentration of H+ at equivalence point is (Kw = 1 \(\times\) 10\(-\)14, at 25\(^\circ\)C)

A solution is made by a concentrated solution of Co(NO3)2 with a concentrated solution of NaNO2 is 50% acetic acid. A solution of a salt containing metal M is added to the mixture, when a yellow precipitate is formed. Metal 'M' is

Indicate the number of unpaired electrons in K3[Fe(CN)6] and K4[Fe(CN)6].

Which of the following compounds have magnetic moment identical with [Cr(H2O)6]3+ ?

A solution of NaNO3, when treated with a mixture of Zn dust and 'A' yields ammonia. 'A' can be

Which of the following solutions will have highest conductivity?

The reduction potential of hydrogen half-cell will be negative if

Molecular velocities of two gases at the same temperature (T) are u1 and u2. Their masses are m1 and m2 respectively. Which of the following expressions is correct at temperature T?

The maximum number of atoms that can be in one plane in the molecule p-nitrobenzonitrile are

p-nitro-N, N-dimethylaniline cannot be represented by the resonating structures.

Which structure has delocalised \(\pi\)-electrons?

Among the following chlorides the compounds which will be hydrolysed most easily and most slowly in aqueous NaOH solution are respectively:1. Methoxymethyl chloride2. Benzyl chloride3. Neopentyl chloride4. Propyl chloride

The compounds X and Y are respectively

The exact order of boiling points of the compounds n-pentane, isopentane, butanone and 1-butanol is

Solubility products (Ksp) of the salts of types MX, MX2 and M3X at temperature T are 4.0 \(\times\) 10\(-\)8, 3.2 \(\times\) 10\(-\)14 and 2.7 \(\times\) 10\(-\)15 respectively. Solubilities (in mol dm\(-\)3) of the salts at temperature T a...

A saturated solution of BaSO4 at 25\(^\circ\)C is 4 \(\times\) 10\(-\)5 M. The solubility of BaSO4 in 0.1 M Na2SO4 at this temperature will be

Aqueous solution of HNO3, KOH, CH3COOH and CH3COONa of identical concentration are provided. The pair(s) of solutions which form a buffer upon mixing is (are)

The relationship between the pair of compounds shown above are respectively

When 20 g of naphthoic acid (C11H8O2) is dissolved in 50 g of benzene, a freezing point depression of 2K is observed. The van't Hoff factor (i) is [Kf = 1.72 K kg mol\(-\)1]

Extraction of a metal (M) from its sulphide ore (M2S) involves the following chemical reactions\(2{M_2}S + 3{O_2}\buildrel {Heat} \over \longrightarrow 2{M_2}O + 2S{O_2} \uparrow\)$${M_2}S + 2{M_2}O\buildrel {Heat} \over
\longrightarrow ...

5.75 mg of sodium vapour is converted to sodium ion. If the ionisation energy of sodium is 490 kJ mol\(-\)1 and atomic weight is 23 units, the amount of energy needed for this conversion will be

For the reaction \(_7^{14}N(\alpha ,p)\,{}^{17}O\), 1.16 MeV (Mass equivalent = 0.00124 amu) of energy is absorbed. Mass on the reactant side is 18.00567 amu and proton mass = 1.00782 amu. The atomic mass of \({}^{17}O\) will be

A given amount of Fe2+ is oxidised by x mol of \(MnO_4^ -\) in acidic medium. The number of moles of \(C{r_2}O_7^{2 - }\) required to oxidise the same amount of Fe2+ in acidic medium is

N2H4 and H2O2 show similarity in

An element crystallises in a body centered cubic lattice. The edge length of the unit cell is 200 pm and the density of the element is 5.0 g cm\(-\)3. Calculate the number of atoms in 100 g of this element.

The mole fraction of a solute in a binary solution is 0.1 at 298 K, molarity of this solution is same as its molality. Density of this solution at 298 K is 2.0 g cm\(-\)3. The ratio of molecular weights of the solute and the solvent (Msolut...

Cyclo [18] carbon is an allotrope of carbon with molecular formula C18. It is a ring of 18 carbon atoms, connected by single and triple bonds. The total number of triple bonds present in this cyclocarbon are

Reaction of silver nitrate solution with phosphorus acid produces

Indicate the products (X) and (Y) in the following reactionsNa2S + nS(n = 1 \(-\) 8) \(\to\) (X)Na2SO3 + S \(\to\) (Y)

The white precipitate (Y), obtained on passing colorless and odourless gas (X) through an ammoniacal solution of NaCl, losses about 37% of its weight on heating and a white residue (Z) of basic nature is left. Identify (X), (Y) and (Z) from...

For a spontaneous reaction at all temperatures which of the following is correct?