Important 2 Marks Questions for CBSE 11 Chemistry Exam

Ques 1:

Why does the rainwater normally have a pH of about 5.6? When does it become acid rain?

Ques 2:

A compound C7 H14  on ozonolysis gives ethanal and pentan–3- one. What is the structure of alkene?

Ques 3:

A metal ‘X’ is present in chlorophyll. Identify the metal ‘X’. How does this metal react with N2?

Ques 4:

An element ‘A’ belongs to group 2 of the periodic table. It shows anomalous behaviour from the rest of the elements of its group. It shows a diagonal relationship with another element ‘B’. Chlorides of both ‘A’ and ‘B’ have bridged structure in vapour phase. Identify A and B and draw the structures of their respective chlorides.

Ques 5:

Consider the reaction of water with F2 and suggest, in terms of oxidation and reduction, which species are oxidized/ reduced.

Ques 6:

Critical temperature of ammonia and carbon dioxide are 405.5 K and 304.10 K respectively. Which these gases will liquefy first when you start cooling from 500K to their critical temperature

Ques 7:

The drain cleaner contains small bits of aluminium which react with caustic soda to produce dihydrogen gas. What volume of dihydrogen at 20°C and one CBSE Board Class XI Chemistry bar pressure will be released when 0.15 g of aluminium reacts

Ques 8:

(a) Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

(b) Out of the elements Cr (Z = 24), Mg (Z=12) and Fe (Z =26), identify the element with five electrons in 3d subshell.

Ques 9:

Which of the following statements related to the modern periodic table is incorrect and why?

(a) Each block contains a number of columns equal to the number of electrons that can occupy that subshell.

(b) The d – block has 8 columns, because a maximum 8 electrons can occupy all the orbitals in d – sub shell.

Ques 10:

Among the elements B, Al, C and Si:

(a) Which has the highest first ionization enthalpy?

(b) Which has the most negative electron gain enthalpy? Give reason

Ques 11:

What is shielding effect? How it affects atomic size in lanthanides?

Ques 12:

Find the number of moles of 4.9g of sulphuric acid?

Ques 13:

Show how hyperconjugation occurs in propene molecule

Ques 14:

How can you explain the formation of NaCl according to Kossel concept?

Ques 15:

What is a black body? What are the characteristics of black body radiation?

Ques 16:

Why is Ga smaller in size than Al?

Ques 17:

Express 32.392800 to four significant figures

Ques 18:

If a tank is full of water coming in and out at the same rate, then what will happen to the level of water in a tank?

Ques 19:

Why the bottle containing hydrogen peroxide should be cooled before opening?

Ques 20:

Why the symbols of $_{35}^{79}\textrm{Br}$  and $_{35}Ba$ are not acceptable?