JEE Main entrance exam Question Bank Solutions

In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainty with which the position of the electron can be located is ______.

(h = 6.6 × 10⁻³⁴ kg m²s⁻¹, mass of electron, e_m = 9.1 × 10⁻³¹ kg)

Which molecule/ion among the following cannot act as a ligand in complex compounds?

During the denaturation of proteins, which of these structures will remain intact?

The polymer used for optical lenses is ______.

3-Methyl-pent-2-ene on reaction with HBr in presence of peroxide forms an addition product. The number of possible stereoisomers for the product is ______.

In the presence of peroxide, HCl and HI do not give anti-Markovnikov's addition of alkenes because ______.

In Carius method, halogen containing organic compound is heated with fuming nitric acid in the presence of ______.

Which of the following is the correct plot for the probability density ψ² (r) as a function of distance 'r' of the electron from the nucleus for 2s orbitals?

1.2 mL of acetic acid is dissolved in water to make 2.0 L of solution. The depression in freezing point observed for this strength of acid is 0.0198° C. The percentage of dissociation of the acid is ______. [Nearest integer]

[Given: Density of acetic acid is 1.02 g mL^–1, Molar mass of acetic acid is 60 g/mol.]

K_f(H₂O) = 1.85 K kg mol^–1

Assertion A: The dihedral angles in H₂O₂ in gaseous phase is 90.2° and in solid phase is 111.5°.

Reason R: The change in dihedral angle in solid and gaseous phase is due to the difference in the intermolecular forces.
Choose the most appropriate answer from the options given below for A and R.7

Major Product In the above chemical reaction, intermediate "X" and reagent/condition "A" are:

Which one of the following complexes is violet in colour?

Of the following four aqueous solutions, total number of those solutions whose freezing points is lower than that of 0.10 M C₂H₅OH is ______. (Integer answer)

1. 0.10 M Ba₃ (PO₄)₂
2. 0.10 M Na₂ SO₄
3. 0.10 M KCl
4. 0.10 M Li₃ PO₄ 

1000 g of 1 m sucrose solution in water is cooled to −3.534°C. What weight of ice would be separated out at this temperature 1 is ______ gm. K_f(H₂O) = 1.86 K mol⁻¹ Kg)

Enthalpy for the reaction \[\ce{Ag+ (aq) + Br- (aq) -> AgBr(s)}\] is : 90 kJ. Magnitude of enthalpy of formation of Ag⁺ (aq) and Br^- (aq) are in the ratio 5 : 6. Formation of Ag⁺(aq) is an endothermic process whereas formation of Br is an exothermic process. Enthalpy of formation of AgBr is - 110 kJ/ mol. The enthalpy of formation of Ag⁺ (aq) will be ______ kJ/mol.

40 g of glucose (Molar mass = 180) is mixed with 200 mL of water. The freezing point of solution is ______ K. (Nearest integer)

[Given : K_f = 1.86 K kg mol^-1; Density of water = 1.00 g cm^-3; Freezing point of water = 273.15 K]

Enthalpy for the reaction \[\ce{Ag^+ (aq) + Br^- (aq) -> AgBr(s)}\] is −84.54 kJ. Magnitude of enthalpy of formation of Ag⁺ (aq) and Br⁻ (aq) are in the ratio 8 : 9. Formation of Ag⁺ (aq) is an endothermic process whereas formation of Br⁻ (aq) is an exothermic process. Enthalpy of formation of AgBr is −99.54 kJ/mol. The enthalpy of formation of Ag⁺ (aq) is ______ kJ/mol.

Two pi and half sigma bonds are present in ______.

Aniline dissolved in dilute HCl is reacted with sodium nitrate at 0 °C. This solution was added dropwise to a solution containing equimolar mixture of aniline and phenol in dil. HCl. The structure of the major product is:

Hydrogen peroxide, in its pure state, is ______.