Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Chemistry

Which relationship is not correct?

The boiling points of hydrides of group 16 are in the order:

The formation of \[\ce{O^+_2[PtF6]^-}\] is the basis for the formation of first xenon compound. This is because ____________.

Which of the following statement is incorrect?

Match the items of Columns I and II and mark the correct option.

Assertion: Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution.

Reason: Nitro group, being an electron-withdrawing group decreases the electron density over the benzene ring.

Which of the following is an example of a solid solution?

Given below are two statements labelled as Assertion (A) and Reason (R).

Assertion (A): Electron gain enthalpy of oxygen is less than that of Flourine but greater than Nitrogen.

Reason (R): Ionisation enthalpies of the elements follow the order Nitrogen > Oxygen > Fluorine.

Select the most appropriate answer from the options given below:

The correct order of the packing efficiency in different types of unit cells is ______.

The edge lengths of the unit cells in terms of the radius of spheres constituting fcc, bcc and simple cubic unit cell are respectively ______.

Assertion: The total number of atoms present in a simple cubic unit cell is one.
Reason: Simple cubic unit cell has atoms at its corners, each of which is shared between eight adjacent unit cells.

If two liquids A and B form minimum boiling azeotrope at some specific composition then ______.

Intermolecular forces between two benzene molecules are nearly of same strength as those between two toluene molecules. For a mixture of benzene and toluene, which of the following are not true?

(i) ∆_mix H = zero

(ii) ∆_mix V = zero

(iii) These will form minimum boiling azeotrope.

(iv) These will not form ideal solution.

Concentration terms such as mass percentage, ppm, mole fraction and molality are independent of temperature, however molarity is a function of temperature. Explain.

Why soda water bottle kept at room temperature fizzes on opening?

What is “semi permeable membrane”?

Assertion: Molarity of a solution in liquid state changes with temperature.

Reason: The volume of a solution changes with change in temperature.

Assertion: When a solution is separated from the pure solvent by a semipermeable membrane, the solvent molecules pass through it from pure solvent side to the solution side.

Reason: Diffusion of solvent occurs from a region of high concentration solution to a region of low concentration solution.

Explain the terms ideal and non-ideal solutions in the light of forces of interactions operating between molecules in liquid solutions.

In the electrolysis of aqueous sodium chloride solution which of the half cell reaction will occur at anode?