List of top Chemistry Questions

20 mL of 0.02 M K₂Cr₂O₇ solution is used for the titration of 10 mL of Fe²⁺ solution in the acidic medium. The molarity of Fe²⁺ solution is ______×10^–2 M. (Nearest integer)

2NO + 2H₂ → N₂ + 2H₂O
The above reaction has been studied at 800 °C. The related data is given in the table below.
The order of the reaction with respect to NO is ___.

Amongst the following, the number of oxide(s) which are paramagnetic in nature is
Na₂O, KO₂, NO₂, N₂O, ClO₂, NO, SO₂, Cl₂O

The molar heat capacity for an ideal gas at constant pressure is 20.785 J K^–1 mol^–1. The change in internal energy is 5000 J upon heating it from 300 K to 500 K. The number of moles of the gas at constant volume is _____. (Nearest integer)
(Given : R = 8.314 JK-1mol-1).

According to MO theory, number of species/ions from the following having identical bond order is ___.
CN-, NO+, O2, O+2, O2+2

At 310 K, the solubility of CaF₂ in water is 2.34 ×10^–3 g/100 mL. The solubility product of CaF₂ is _____ × 10^–8 (mol/L)³.
(Given molar mass : CaF₂ = 78 g mol^–1).

The conductivity of a solution of complex with formula CoCl₃(NH₃)₄ corresponds to 1 : 1 electrolyte, then the primary valency of central metal ion is ______.

Write the product when alkyl halide reacts with silver nitrite.

At 30ºC, the half life for the decomposition of \(AB_2\) is 200 s and is independent of the initial concentration of \(AB_2\). The time required for 80% of the \(AB_2\) to decompose is(Given : \(log\; 2 = 0.30,\; log \;3 = 0.48\))

Which of the following pair of molecules contain odd electron molecule and an expanded octet molecule?

\(N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)\)
Consider the above reaction, the limiting reagent of the reaction and number of moles of NH₃ formed, respectively are :

100 mL of 5% (w/v) solution of NaCl in water was prepared in 250 mL beaker. Albumin from the egg was poured into NaCl solution and stirred well. This resulted in a/an :

The minimum uncertainty in the speed of an electron in an one dimensional region of length 2a₀ (Where a₀ = Bohr radius 52.9 pm) is _____ km s^–1.
(Given : Mass of electron = 9.1 × 10^–31 kg, Planck’s constant h = 6.63 × 10^–34Js)

When 600 mL of 0.2 M HNO₃ is mixed with 400 mL of 0.1 M NaOH solution in a flask, the rise in temperature of the flask is ________ × 10^–2 °C.
(Enthalpy of neutralisation = 57 kJ mol^–1 and Specific heat of water = 4.2 JK^–1 g^–1)
(Neglect heat capacity of flask)

The first ionization enthalpy of Na, Mg and Si, respectively, are : 496, 737 and 786 kJ mol^–1. The first ionization enthalpy (kJ mol^–1) of Al is:

If O₂ gas is bubbled through water at 303 K, the number of millimoles of O₂ gas that dissolve in 1 litre of water is_______. (Nearest integer)
(Given : Henry’s Law constant for O₂ at 303 K is 46.82 k bar and partial pressure of O₂ = 0.920 bar)
(Assume solubility of O₂ in water is too small, nearly negligible)

In metallurgy the term “gangue” is used for :

Resistance of a conductivity cell (cell constant 129 m^–1) filled with 74.5 ppm solution of KCI is 100 Ω (labelled as solution 1). When the same cell is filled with KCl solution of 149 ppm, the resistance is 50 Ω (labelled as solution 2). The ratio of molar conductivity of solution 1 and solution 2 is \(\frac{\Lambda_1}{\Lambda_2} = x \times 10^{-3}\). The value of x is _________. (Nearest integer)
(Given : molar mass of KCl is 74.5 g mol^–1).

If the solubility product of PbS is 8 × 10^–28, then the solubility of PbS in pure water at 298 K is x × 10^–16 mol L^–1. The value of x is ________. (Nearest integer)
[given : \(\sqrt2=1.41\)]

A 10 g mixture of hydrogen and helium is contained in a vessel of capacity 0.0125 m³ at 6 bar and 27°C. The mass of helium in the mixture is _______ g. (nearest integer)
Given : R = 8.3 J K^–1 mol^–1
(Atomic masses of H and He are 1 u and 4 u, respectively)

Ionic radii of cation A⁺ and anion B^– are 102 and 181 pm, respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for B^–. A⁺ is present in all octahedral voids. The edge length of the unit cell of the crystal AB is _____pm. (Nearest integer)

The reaction between X and Y is first order with respect to X and zero order with respect to Y.

Examine the data of table and calculate ratio of numerical values of M and L. (Nearest integer)