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

4 L of 0.02 M aqueous solution of NaCl was diluted by adding one litre of water. The molality of the resultant solution is ______.

Cone. H₂SO₄ is 98% H₂SO₄ by mass has d = 1.84 g cm⁻³. Volume of acid required to make one litre of 0.1 M H₂SO₄ is:

What is the mole fraction of solute in 1.00 m aqueous solutions?

\[\begin{array}{cc}
\ce{CH3-CH-CH=CH2 + HBr -> A}\\
|\phantom{.....................}\\
\ce{CH3}\phantom{..................}
\end{array}\]

'A' is:

The heating of phenyl methyl ether with HI produces:

Which of the following gives a positive iodoform test?

\[\ce{Phenol ->[Zn, dust] 'X' ->[CH3Cl][Anhy. AlCl3] 'Y' ->[Alkaline][KMnO4] 'Z'}\]

The product ‘Z’ is:

Among the following sets of reactants which one produces anisole?

IUPAC name of the compound is:

\[\begin{array}{cc}
\ce{CH3-CH-OCH3}\\
|\phantom{....}\\
\ce{CH3}\phantom{..}
\end{array}\]

The correct acidic strength order of the following is:

     (I)

    (II)

     (III)

Which of the following is a correct statement for C₂H₅Br?

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

Assertion (A): Molarity of a solution changes with temperature.

Reason (R): Molarity is a colligative property.

Select the most appropriate answer from the options given below:

Which of the following is not true about the ionic solids?

An excess of potassium ions makes KCl crystals appear violet or lilac in colour since:

(i) some of the anionic sites are occupied by an unpaired electron.

(ii) some of the anionic sites are occupied by a pair of electrons.

(iii) there are vacancies at some anionic sites.

(iv) F-centres are created which impart colour to the crystals.

Which of the following cannot be regarded as molecular solid?

(i) SiC (Silicon carbide)

(ii) AlN

(iii) Diamond

(iv) I₂ 

Why are liquids and gases categorised as fluids?

Inspite of long range order in the arrangement of particles why are the crystals usually not perfect?

Match the terms given in Column I with expressions given in Column II.

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

w/w (mass percentage)

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

V/V (volume percentage)