S- Block Elements: Chemistry

• Answers are in BOLD Option name.

 Q.1.  A Combustible gas is liberated when caustic soda solution is heated with 

A) S

B) NHCI

C) I

D) Zn

Explanation-

2NaOH+Zn 

Q.2.  On dissolving moderate amount of sodium metal in liquid ammonia at low temperature , which one of the following does not occur 

A) Blue coloured solution is obtained 

B) Na  ions are formed in the solution 

C) Liquid ammonia becomes good conductor of electricity 

D) Liquid ammonia remains diamagnetic 

Explanation-

Liquid ammonia solution becomes paramagnetic due to the presence of unpaired electron ions in the cavities in ammoniacal solution.

Q.3. Which of the following has largest size ?

A) Na

B) Na

C) Na

D) None of the above 

Explanation-

Anions has larger size than their parent atom.

Q.4.  When washing soda is heated 

A) CO is released 

B) CO+CO  is released 

C) CO  is released

D) Water vapour is released 

Explanation-

 

Q.5.  In Solvay ammonia process, sodium bicarbonate is precipitated due to 

A) Presence of NH 

B) Reaction with CO 

C) Reaction with brine solution 

D) Reaction with NaOH

Explanation-

In Solvay ammonia process, sodium bicarbonate is precipitated due to common ion() effect provided by brine (concentrated NaCl solution).

Q.6.  In electrolysis of NaCl , when Pt electrode is taken then H is liberated at cathode while with Hg cathode it forms sodium amalgam . The reason for this is 

A) Hg is more inert than Pl

B) More voltage is required to reduce H at Hg than at Pt 

C) Na is dissolved in Hg while it does  not dissolve in Pt

D) Concentration of  H ions is larger when Pt electrode is taken 

Explanation-

More voltage is required to reduce  at Hg than at Pt.

Q.7.  When CO is bubbled into an aqueous solution of NaCO, the following is formed 

A) NaOH

B) NaHCO

C) HO

D) OH 

Explanation-

 

Q.8.  ion imparts violet color to the flame .This is due to the fact  that the emitted radiations have 

A) High energy 

B) Low energy 

C) Longer wavelength 

D) None of these 

Explanation-

Violet color corresponds to low wavelength or higher energy.

Q.9.  Sodium nitrate decomposes above 800 C to give 

A) N

B) O

C) NO

D) NaO

Explanation-

 

Q.10. 1) The s- block elements of the periodic table are those in  which the last electron enters the s- subshell of the ________shell.

A) penultimate

B) antepenultimate

C) outermost          

D) foremost

Explanation-

Last electron , also called differentiating electron, enters the s- orbital of the last shell. Thus their general valence shell electron configuration is  .