MgO + 2HCl —-> X + H2O a) Mg2Cl b) 2MgCl c) MgCl d) MgCl2
The Correct Answer and Explanation is:
The correct answer is: d) MgCl₂
Explanation
The balanced chemical reaction is: MgO+2HCl→MgCl2+H2O\text{MgO} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2\text{O}
This is an acid-base reaction between magnesium oxide (MgO) and hydrochloric acid (HCl).
Step-by-Step Analysis:
- Reactants:
- MgO (Magnesium oxide): A basic oxide, which means it can react with acids to form a salt and water.
- HCl (Hydrochloric acid): A strong acid that dissociates completely in water to release H⁺ and Cl⁻ ions.
- Reaction Mechanism:
- Magnesium oxide reacts with two molecules of hydrochloric acid.
- The oxide ion (O²⁻) from MgO reacts with two hydrogen ions (2H⁺) from HCl to form H₂O (water).
- The magnesium ion (Mg²⁺) from MgO then combines with two chloride ions (2Cl⁻) from HCl to form magnesium chloride (MgCl₂).
- Balanced Equation:
MgO+2HCl→MgCl2+H2O\text{MgO} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2\text{O}
- One molecule of MgO reacts with two molecules of HCl.
- This yields one molecule of MgCl₂ and one molecule of water.
Why the Answer is MgCl₂ (d):
- Magnesium (Mg) has a +2 charge.
- Chloride (Cl) has a –1 charge.
- Therefore, to neutralize the charges, two chloride ions are needed for every one magnesium ion, forming MgCl₂.
- This matches answer (d).
Incorrect Options:
- a) Mg₂Cl: Incorrect formula — no such stable compound.
- b) 2MgCl: Incorrect stoichiometry and valency — MgCl doesn’t match magnesium’s +2 charge.
- c) MgCl: Also incorrect — requires two Cl⁻ ions to balance Mg²⁺.
Conclusion:
The correct product of the reaction between MgO and HCl is MgCl₂, making option d the correct answer.
