12 gm of Mg (Atomic mass = 24) will react with an acid to give:
Correct answer: C. Half mole of H2
- A. One mole of H2
- B. One mole of O2
- C. Half mole of H2
- D. Half mole of O2
Explanation
When magnesium (Mg) reacts with an acid, it typically displaces hydrogen, forming hydrogen gas (H2). The balanced chemical equation for this reaction is:Mg + 2H+ → Mg2+ + H2From this equation, we see that one mole of Mg produces one mole of H2. Since we have 12 g of Mg, which is 0.5 moles (12 g / 24 g/mol), it will produce 0.5 moles of H2 gas. Therefore, the correct answer is 'Half mole of H2'.Options A and D are incorrect because they suggest incorrect stoichiometric relationships, and Option B is incorrect because O2 is not produced in this reaction.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Fundamental Concepts of Chemistry
Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.
Practise Fundamental Concepts of Chemistry
894 free Fundamental Concepts of Chemistry MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Fundamental Concepts of Chemistry questions
112 ml of a gas is produced at STP by the action of 0.412 gm of ROH alcohol with CH3Mgl. Molecular mass of alcohol is:
A 0.1097 gm sample of As2O3 required 26.10 mL of KMnO4 solution for its titration. The molarity of KMnO4 solution is:
When a 3.0 litre solution of normality N is mixed with 5.0 liter of 4M HCl, then the resultant solution has the normality 10. Find the value of N.
When pentane C5H12 is burned in excess oxygen, the products of the reaction are CO2(g) and H2O(l). In the balanced equation for this combustion,C5H12(g) _ O2 (g) → 5CO2(g) + 6H2O(l) the coefficient of the oxygen should be:
When 16.6 g of KI is treated with an excess of KIO3 in the presence of 6NHCl, ICl is produced. The amount of KIO3 consumed and the ICl formed are:
The number of ions present in 2.0 L of a solution of 0.8 M K4 [Fe(CN)6] is: