ScienceCBSE Class 10 · Board exam 2023, set 31/1/1 · 1 mark · MCQ

CBSE Class 10 Science 2023: question 5

Set in the CBSE Class 10 board exam of 2023, paper 31/1/1, section A, question 5, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q5 · 1 mark · MCQMetals and Non-metals

A metal 'X' is used in thermite process. When X is burnt in air it gives an amphoteric oxide 'Y'. 'X' and 'Y' are respectively :

(A)Fe and $F e_{2} O_{3}$
(B) $A l$ and $A l_{2} O_{3}$
(C)Fe and $F e_{3} O_{4}$
(D) $A l$ and $A l_{3} O_{4}$

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/1/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Which metal reduces iron oxide in the thermite reaction?

Hint 2

Aluminium has valency 3. Write the correct formula of its oxide.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

The thermite process uses aluminium as the reducing agent: $F e_{2} O_{3} + 2Al \to 2Fe + A l_{2} O_{3} + heat$ . So X = Al.
Aluminium burns to form $A l_{2} O_{3}$ , an amphoteric oxide. ( $A l_{3} O_{4}$ is not a real formula.) So the answer is (B).
1 mark

Answer: X = Al, Y = Al₂O₃; option (B)

Where the marks are

Identifies Al and $A l_{2} O_{3}$ , option (B) (1 mark)

Revise the chapter

Chapter: Metals and Non-metals (notes, formulas, where marks are lost and every past question)

Practise this chapterBoard-style questions from Metals and Non-metals, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 31/1/1: every question, by section.

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CBSE Class 10 Science 2023: question 5

Hints

Step-by-step solution

Revise the chapter

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