In the case of alkali metals, the covalent character decreases in the order

1. MCl>Ml>MBr>MF

2. MF>MCl>MBr>Ml

3. MF>MCl>Ml>MBr

4. Ml>MBr>MCl>MF

The correct order of increasing thermal stability of K₂CO₃, MgCO₃, CaCO₃ and BeCO₃ is :

1. ${\mathrm{BeCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{K}}_2{\mathrm{CO}}_3<{\mathrm{CaCO}}_3$

2. ${\mathrm{BeCO}}_3<{\mathrm{MgCO}}_3<{\mathrm{CaCO}}_3<{\mathrm{K}}_2{\mathrm{CO}}_3$

3. ${\mathrm{MgCO}}_3<{\mathrm{BeCO}}_3<{\mathrm{CaCO}}_3<{\mathrm{K}}_2{\mathrm{CO}}_3$

4. ${\mathrm{K}}_2{\mathrm{CO}}_3<{\mathrm{MgCO}}_3<{\mathrm{CaCO}}_3<{\mathrm{BeCO}}_3$

The gas released when baking soda is mixed with vinegar is 

1. CO

2. CO₂

3. CH₄

4. O₂

When treated with conc. HCl, MnO₂ yields a gas (X) which further reacts with Ca(OH)₂ to generate a white solid (Y). The solid Y reacts with dil. HCl to produce the same gas X. The solid Y is                                     

1. CaO

2. CaCl₂

3. Ca(OCl)Cl

4. CaCO₃

The thermal stability of alkaline earth metal carbonates-MgCO₃, CaCO₃, SrCO₃ and BaCO₃, follows the order.                               

1. BaCO₃>SrCO₃>CaCO₃>MgCO₃

2. CaCO₃>SrCO₃>BaCO₃>MgCO₃

3. MgCO₃>CaCO₃>SrCO₃>BaCO₃

4. SrCO₃>CaCO₃>MgCO₃>BaCO₃

CO₂ is passed through lime water. Initially the solution turns milky and then becomes clear upon continued bubbling of CO₂. The clear solution is due to the formation of                                                                  

1. CaCO₃

2. CaO

3. Ca(OH)₂

4. Ca(HCO₃)₂

The most abundant metal  ion present in the human body is 

1. Zn²⁺

2. Ca²⁺

3. Na⁺

4. Fe²⁺

The alkali metals are low melting. Which of the following alkali metal is expected
to melt if the room temperature rises to 30°C?

1. Na

2. K

3. Rb

4. Cs 

Alkali metals react with water vigorously to form hydroxides and dihydrogen.
Which of the following alkali metals reacts with water least vigorously?

1. Li

2. Na

3. K

4. Cs

The reducing power of a metal depends on various factors. Suggest the factor
which makes Li, the strongest reducing agent in aqueous solution.

1. Sublimation enthalpy

2. Ionisation enthalpy

3. Hydration enthalpy

4. Electron-gain enthalpy