JEE Main entrance exam Question Bank Solutions for Chemistry (JEE Main)

What is DDT among the following?

Which of the following statements about low density polythene is false?

Which of the following is structure of a separating funnel ?

The stepwise formation of [Cu(NH₃)₄]²⁺ is given below:

\[\ce{Cu^{2+} + NH3 <=>[K1] [Cu(NH3)]^{2+}}\]

\[\ce{[Cu(NH3)]^{2+} + NH3 <=>[K2] [Cu(NH3)2]^{2+}}\]

\[\ce{[Cu(NH3)2]^{2+} + NH3 <=>[K3] [Cu(NH3)3]^{2+}}\]

\[\ce{[Cu(NH3)3]^{2+} + NH3 <=>[K4] [Cu(NH3)4]^{2+}}\]

The value of stability constants K₁, K₂, K₃ and K₄ are 10⁴, 1.58 × 10², 5 × 10³ and 10² respectively. The overall equilibrium constant for dissociation of [Cu(NH₃)₄]²⁺ is x × 10⁻¹². The value of x is ______. (Rounded-off to the nearest integer)

At 1990 K and 1 atm pressure, there are equal numbers of Cl₂ molecules and Cl atoms in the reaction mixture. The value of K_p for the reaction Cl₂(g) ⇌ 2Cl(g) under the above conditions is x × 10⁻¹. The value of x is ______. (Rounded-off to the nearest integer)

In chromatography technique, the purification of compound is independent of ______.

The process that involves the removal of sulphur from the ores is ______.

For the reaction \[\ce{A(g) <=> B(g)}\] at 495 K, ΔG° = −9.478 kJ mol⁻¹

If we start the reaction in a closed container at 495 K with 22 millimoles of A, the amount of B in the equilibrium mixture is ______ millimoles. (Round off to the Nearest Integer).

[R = 8.314 J mol⁻¹ K⁻¹; ln 10 = 2.303]

The polymer formed on heating Novolac with formaldehyde is ______.

An equilibrium system for the reaction between hydrogen and iodine to give hydrogen iodide at 765 K in a 5 litre volume contains 0.4 mole of hydrogen, 0.4 mole of iodine and 2.4 moles of hydrogen iodide.

\[\ce{H2 + I2 <=> 2HI}\]

The equilibrium constant for the reaction is:

A sample of U²³⁸ (half-life = 4.5 × 10⁹ years) ore is found to contain 23.8 g of U²³⁸ and 20.6 g of Pb²⁰⁶. The age of the ore is ______ × 10⁹ years.

The half-life of cobalt 60 is 5.26 years. The percentage activity remaining after 4 years is ______%.

A solution of a non-volatile solute in water freezes at −0.30°C. The vapour pressure of pure water at 298 K is 23.51 mm Hg and K_f for water is 1.86 degree/mol. The vapour pressure of rain solution at 298 K is ______ mm Hg.

Sulphide ion in alkaline solution reacts with solid sulphur to form polysulphide ions having formula, \[\ce{S^{2-}2}\], \[\ce{S^{2-}3}\], \[\ce{S^{2-}4}\], etc. if K₁ = 12 for \[\ce{S + S^{2-} <=> S^{2-}2}\] and K₂ = 132 for \[\ce{2S + S^{2-} <=> S^{2-}3}\], K₃ = ______ for \[\ce{S + S^{2-}2 <=> S^{2-}3}\].

The total number of α and β particles emitted in the nuclear reaction \[\ce{^238_92U -> ^214_82Pb}\] is ______.

The density of gold is 19 g/cm³. If 1.9 × 10^{−4 g} of gold is dispersed in one litre of water to give a sol having spherical gold particles of radius 10 nm, the number of gold particles per mm³ of the sol will be ______ × 10⁶.

The amount of C-14 isotope in a piece of wood is found to be 1/16^th of its amount present in a fresh piece of wood. The age of wood, half-life period of C-14 is 5770 years, is ______ years.

For which of the following K_p is less than K_c?

The weight of CO is required to form Re₂(CO)₁₀ will be ______ g, from 2.50 g of Re₂O₇ according to given reaction

\[\ce{Re2O7 + CO -> Re2(CO)10 + CO2}\]

Atomic weight of Re = 186.2; C = 12 and O = 16.

The equilibrium constant for the reaction is ______ × 10²⁶.

\[\ce{Fe + CuSO4 <=> FeSO4 + Cu}\] at 25°C.

Given `"E"_("Fe"//"Fe"^(2+))^0` = 0.44 V

`"E"_("Cu"//"Cu"^(2+))^0` = - 0.337 V