Science (English Medium) कक्षा ११ - CBSE Question Bank Solutions

Which of the following ions will cause hardness in water sample?

Which of the following compounds is used for water softening?

Hardness of water may be temporary or permanent. Permanent hardness is due to the presence of:

(i) Chlorides of \[\ce{Ca}\] and \[\ce{Mg}\] in water.

(ii) Sulphates of \[\ce{Ca}\] and \[\ce{Mg}\] in water.

(iii) Hydrogen carbonates of \[\ce{Ca}\] and \[\ce{Mg}\] in water.

(iv) Carbonates of alkali metals in water.

Complete the following equations:

\[\ce{PbS (s) + H2O2 (aq) ->}\]

Complete the following equations:

\[\ce{CO (g) + 2H2 (g) ->[Cobalt][Catalyst]}\]

Discuss briefly de-mineralisation of water by ion exchange resin.

Why is the Ionisation enthalpy of hydrogen higher than that of sodium?

Match the items in Column I with the relevant item in Column II.

Assertion (A): Permanent hardness of water is removed by treatment with washing soda.

Reason (R): Washing soda reacts with soluble magnesium and calcium sulphate to form insoluble carbonates.

If a trivalent atom replaces a few silicon atoms in three-dimensional network of silicon dioxide, what would be the type of charge on overall structure?

Match the ions given in Column I with their nature given in Column II.

Arrange the halogens F₂, Cl₂, Br₂, I₂, in order of their increasing reactivity with alkanes.

The addition of HBr to 1-butene gives a mixture of products A, B and C

(A)
(B)
(C)	CH3 – CH2 – CH2 – CH2 – Br

The mixture consists of:

Arrange the following hydrogen halides in order of their decreasing reactivity with propene.

Which of the following alkenes on ozonolysis give a mixture of ketones only?

(i)	CH3 – CH = CH – CH3
(ii)	\[\begin{array}{cc} \ce{CH3 - C - CH = CH2}\\ |\phantom{.......}\\ \ce{CH3}\phantom{....} \end{array}\]
(iii)
(iv)	\[\begin{array}{cc} \phantom{...................}\ce{CH3}\\ \phantom{..............}/\\ \ce{(CH3)2 C = C}\\ \phantom{..............}\backslash\\ \phantom{...................}\ce{CH3} \end{array}\]

In the presence of peroxide addition of HBr to propene takes place according to anti Markovnikov’s rule but peroxide effect is not seen in the case of HCl and HI. Explain.

An alkene ‘A’ contains three C – C, eight C – H σ bonds and one C – C π bond. ‘A’ on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write the IUPAC name of ‘A’.

An alkene ‘A’ contains three C-C, eight C-H σ bonds and one C-C π bond. ‘A’ on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write the IUPAC name of ‘A’.

What is the basic difference between the terms electron gain enthalpy and electronegativity?

How would you react to the statement that the electronegativity of N on Pauling scale is 3.0 in all the nitrogen compounds?