Change set

Pick exam & year, then Go.

Question map
Not attempted Correct Incorrect Bookmarked
Loading…
Q78 (NDA-II/2012) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Basic chemical principles Answer Verified

Which one among the following equations is correctly balanced?

Result
Your answer:  ·  Correct: B
Explanation

The reaction between aluminium (Al), sodium hydroxide (NaOH), and water (H2O) produces sodium aluminate (NaAlO2) and hydrogen gas (H2). To balance this chemical equation, one must ensure the number of atoms for each element is equal on both sides of the reaction. According to the stoichiometry of the balanced equation, 2 moles of aluminium react with 2 moles of sodium hydroxide and 2 moles of water to yield 2 moles of sodium aluminate and 3 moles of hydrogen gas. Specifically, the reactant side contains 2 Na, 2 Al, 6 O (2 from NaOH, 2 from H2O, and 2 from the aluminate structure in some interpretations, though the standard balanced form uses 2 H2O), and 6 H atoms. This matches the product side: 2 Na, 2 Al, 4 O (in 2 NaAlO2), and 6 H (in 3 H2). Thus, option 2 is the correctly balanced representation.

How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
33%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

4 Cross-Linked PYQs

UPSC repeats concepts across years. Login to see how this question connects to 4 others.

Login with Google