UNIT 5: Alkali and Alkaline Earth Metals - Online Test

Q1. For alkali metals, which one of the following trends is incorrect ?
Answer : Option C
Explaination / Solution:

Potassium is lighter than sodium (Refer table 5.3)

The correct order of density is Li < K < Na < Rb < Cs

0.54 < 0.86 < 0.97< 1.53< 1.90(in g cm–3)

Q2. Which of the following statements is incorrect ?
Answer : Option A
Explaination / Solution:

Li+ has maximum degree of hydration among alkali metal cations.

Li+ > Na+ > K+ > Rb+ > Cs+


Q3. Which of the following compounds will not evolve H2 gas on reaction with alkali metals ?
Answer : Option D
Explaination / Solution:

All these compounds reacts with alkali metals to evolve hydrogen gas.

Q4. Which of the following has the highest tendency to give the reaction M+(g) --Aqueous ---Medium → M+(aq)
Answer : Option B
Explaination / Solution:

hydration energy of Li+ is more and hence Li+ is stabilized in aqueous medium.

Q5. Sodium is stored in
Answer : Option C
Explaination / Solution:
No Explaination.


Q6. RbO2 is
Answer : Option A
Explaination / Solution:

RbO2 is a super oxide which contains Rb+ and O2 ions. O2 contains one unpaired electron and hence it is paramagnetic.

Q7. Find the wrong statement
Answer : Option C
Explaination / Solution:

Potassium carbonate cannot be prepared by solvay process. Potassium bicarbonate is fairly soluble in water and does not precipitate out.



Q8. Lithium shows diagonal relationship with
Answer : Option B
Explaination / Solution:




Q9. Incase of alkali metal halides, the ionic character increases in the order
Answer : Option B
Explaination / Solution:

ionic character (difference in electronegativity)

MI < MBr < MCl < MF


Q10. In which process, fused sodium hydroxide is electrolysed for extraction of sodium ?
Answer : Option A
Explaination / Solution:

Castner's process

NaOH ↔ Na+ + OH

Cathode : Na+ + e → Na

Anode : 2OH → H2O + 1/2O2 + 2e