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

For the reaction

`2AgCl (s) + H_2 (g) ("1 atm") -> 2Ag (s) + 2H^(+)  (0.1 M) +  2Cl^(-) (0.1 M)`

`triangleG^0 = -43600 J at 25^@ C`

Calculate the e.m.f. of the cell

`[log 10^(-n) = -n]` 

Draw the structures of the following :

H₂S2O₇

Which of the two components of starch is water soluble?

Define the following with a suitable example, of each: 
 Coagulation 

What is observed when an emulsion is centrifuged?

Out of starch and ferric hydroxide sol, which one can easily be coagulated and why? 

Write equations of the following reactions:
Acetylation of aniline

An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because ______.

Consider the figure and mark the correct option.

Water retention or puffiness due to high salt intake occurs due to ______.

Why are aquatic species more comfortable in cold water in comparison to warm water?

When kept in water, raisin swells in size. Name and explain the phenomenon involved with the help of a diagram. Give three applications of the phenomenon.

In the preparation of \[\ce{H2SO4}\] by Contact Process, why is \[\ce{SO3}\] not absorbed directly in water to form \[\ce{H2SO4}\]?

Write the structure of pyrophosphoric acid.

Match the formulas of oxides given in Column I with the type of oxide given in Column II and mark the correct option.

Assertion: \[\ce{SF6}\] cannot be hydrolysed but \[\ce{SF4}\] can be.

Reason: Six \[\ce{F}\] atoms in \[\ce{SF6}\] prevent the attack of \[\ce{H2O}\] on sulphur atom of \[\ce{SF6}\].

\[\begin{array}{cc}
\ce{CH3 - C ≡ CH ->[40{%} H2SO4][1{%} HgSO4] A ->[Isomerisation] CH3 - C - CH3}\\
\phantom{........................................}||\\
\phantom{........................................}\ce{O}\\
\end{array}\]

Structure of ‘A’ and type of isomerism in the above reaction are respectively.

Arenium ion involved in the bromination of aniline is:

(i)

(ii)

(iii)

(iv)

Why is benzene diazonium chloride not stored and is used immediately after its preparation?

Why does acetylation of –NH₂ group of aniline reduce its activating effect?