ScienceCBSE Class 10 · Board exam 2024, set 31/5/1 · 2 marks · Very short answer

CBSE Class 10 Science 2024: question 21(b)

Set in the CBSE Class 10 board exam of 2024, paper 31/5/1, section B, question 21(b), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21(b) · 2 marks · Very short answerChemical Reactions and Equations

Write chemical equation for the chemical reaction which occurs when the aqueous solutions of barium chloride and sodium sulphate react together. Write the symbols of the ions present in the compound precipitated in the reaction.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/5/1.

Hints

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

Hint 1

The two compounds exchange their ions. Which of the two new products is insoluble in water?

Hint 2

The insoluble product is barium sulphate. Split it into its cation and anion, with their charges.

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.

This is a double displacement (precipitation) reaction. A white precipitate of barium sulphate forms:
$BaC l_{2} (aq) + N a_{2} S O_{4} (aq) \to BaS O_{4} (s) + 2NaCl (aq)$
1 mark
The precipitate $BaS O_{4}$ contains barium ions, $B a^{2 +}$ ,
½ mark
and sulphate ions, $S O_{4}^{2 -}$ .
½ mark

Answer: $B a C l_{2} (a q) + N a_{2} S O_{4} (a q) \to B a S O_{4} (s) + 2 N a C l (a q)$ ; ions $B a^{2 +}$ and $S O_{4}^{2 -}$

Where the marks are

Writes the balanced equation with $B a S O_{4}$ as the precipitate (1 mark)
Gives the ion $B a^{2 +}$ (½ mark)
Gives the ion $S O_{4}^{2 -}$ (½ mark)

Revise the chapter

Chapter: Chemical Reactions and Equations (notes, formulas, where marks are lost and every past question)

Practise this chapterBoard-style questions from Chemical Reactions and Equations, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 31/5/1: every question, by section.

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CBSE Class 10 Science 2024: question 21(b)

Hints

Step-by-step solution

Revise the chapter

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