Class 10 Study of Compounds: Sulphuric Acid Mock Test (ICSE)

Topics in Study of Compounds: Sulphuric Acid

• Contact process
• Sulphuric acid as an acid
• As a dehydrating agent
• As an oxidising agent
• As a non-volatile acid

Study of Compounds: Sulphuric Acid practice questions with answers

1. Q1Multiple choice·1 mark
   Concentrated sulphuric acid acts as a strong dehydrating agent because of its high affinity for which of the following?

   1. (a)Water molecules
   2. (b)Carbon atoms
   3. (c)Hydrogen ions
   4. (d)Oxygen gas
   Show answer and step marks

   1. Correct option: (a) Water molecules. Concentrated $H_2SO_4$ has a strong affinity for water and chemically removes elements of water from compounds like sugar and blue vitriol.+1

   Answer: (a)
2. Q2Multiple choice·1 mark
   Dilute sulphuric acid reacts with active metals to form a salt and hydrogen gas. Which of the following metals does *not* react with dilute $H_2SO_4$ to liberate hydrogen gas?

   1. (a)$Zn$
   2. (b)$Fe$
   3. (c)$Mg$
   4. (d)$Cu$
   Show answer and step marks

   1. Correct option: (d) $Cu$. Copper is less reactive than hydrogen and lies below it in the reactivity series, hence it cannot displace hydrogen from dilute $H_2SO_4$.+1

   Answer: (d)
3. Q3Multiple choice·1 mark
   Concentrated sulphuric acid is used in the laboratory preparation of volatile acids like hydrochloric acid from sodium chloride because it is:

   1. (a)A strong oxidising agent
   2. (b)A powerful dehydrating agent
   3. (c)A dibasic acid
   4. (d)A non-volatile acid
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   1. Correct option: (d) A non-volatile acid. Concentrated $H_2SO_4$ has a high boiling point (is non-volatile) and can therefore displace more volatile acids from their salts when heated.+1

   Answer: (d)
4. Q4Multiple choice·1 mark
   When hot and concentrated sulphuric acid reacts with sulphur, it acts as an oxidising agent and produces:

   1. (a)Hydrogen sulphide and water
   2. (b)Sulphur trioxide only
   3. (c)Hydrogen gas and sulphur dioxide
   4. (d)Sulphur dioxide and water
   Show answer and step marks

   1. Correct option: (d) Sulphur dioxide and water. Hot and concentrated $H_2SO_4$ oxidises non-metals like sulphur to sulphur dioxide, releasing water in the process according to the equation $S + 2H_2SO_{4(conc.)} \xrightarrow{\Delta} 3SO_2 + 2H_2O$.+1

   Answer: (d)
5. Q5Long answer·4 marks
   (a) Give balanced chemical equations with state symbols for the reaction of dilute sulphuric acid with: (i) an active metal such as zinc. (ii) a metallic carbonate such as sodium carbonate. (b) Sulphuric acid is a dibasic acid. Explain this term and write balanced chemical equations to show the stepwise neutralization of sodium hydroxide by sulphuric acid yielding an acid salt and a normal salt.
   Show answer and step marks

   1. (a)(i) $\text{Zn (s)} + \text{H}_2\text{SO}_4\text{ (aq)} \rightarrow \text{ZnSO}_4\text{ (aq)} + \text{H}_2\text{ (g)} \uparrow$+1
   2. (a)(ii) $\text{Na}_2\text{CO}_3\text{ (s)} + \text{H}_2\text{SO}_4\text{ (aq)} \rightarrow \text{Na}_2\text{SO}_4\text{ (aq)} + \text{H}_2\text{O (l)} + \text{CO}_2\text{ (g)} \uparrow$+1
   3. (b) A dibasic acid is one whose molecule ionises in water to give two hydronium ions ($\text{H}_3\text{O}^+$), i.e. it has two replaceable hydrogen atoms per molecule.+1
   4. (b) First step, forming the acid salt: $\text{NaOH (aq)} + \text{H}_2\text{SO}_4\text{ (aq)} \rightarrow \text{NaHSO}_4\text{ (aq)} + \text{H}_2\text{O (l)}$+0.5
   5. (b) Second step, forming the normal salt: $\text{NaHSO}_4\text{ (aq)} + \text{NaOH (aq)} \rightarrow \text{Na}_2\text{SO}_4\text{ (aq)} + \text{H}_2\text{O (l)}$+0.5

   Answer: (a)(i) $\text{Zn (s)} + \text{H}_2\text{SO}_4\text{ (aq)} \rightarrow \text{ZnSO}_4\text{ (aq)} + \text{H}_2\text{ (g)}$; (ii) $\text{Na}_2\text{CO}_3\text{ (s)} + \text{H}_2\text{SO}_4\text{ (aq)} \rightarrow \text{Na}_2\text{SO}_4\text{ (aq)} + \text{H}_2\text{O (l)} + \text{CO}_2\text{ (g)}$. (b) Dibasic: one molecule gives two $\text{H}_3\text{O}^+$ ions (two replaceable H atoms). $\text{NaOH} + \text{H}_2\text{SO}_4 \rightarrow \text{NaHSO}_4 + \text{H}_2\text{O}$ (acid salt), then $\text{NaHSO}_4 + \text{NaOH} \rightarrow \text{Na}_2\text{SO}_4 + \text{H}_2\text{O}$ (normal salt).
6. Q6Long answer·4 marks
   Sulphuric acid is a strong acid. (a) What is the basicity of sulphuric acid? Name the two types of salts formed by it. (b) Write the balanced chemical equation for the complete neutralization of dilute sulphuric acid with caustic soda solution. (c) Write the balanced chemical equation when dilute sulphuric acid reacts with sodium hydroxide in a $1:1$ molar ratio, and write the IUPAC name or common name of the salt formed.
   Show answer and step marks

   1. (a) Basicity of sulphuric acid is $2$.+0.5
   2. (a) The two types of salts formed are normal salts and acid salts.+0.5
   3. (b) Balanced equation for complete neutralization: $H_2SO_{4(aq)} + 2NaOH_{(aq)} \rightarrow Na_2SO_{4(aq)} + 2H_2O_{(l)}$+1.5
   4. (c) Balanced equation for acid salt formation: $H_2SO_{4(aq)} + NaOH_{(aq)} \rightarrow NaHSO_{4(aq)} + H_2O_{(l)}$+1
   5. (c) Name of salt: sodium hydrogensulphate (or sodium bisulphate).+0.5

   Answer: Basicity: 2; Normal and Acid salts; $H_2SO_{4(aq)} + 2NaOH_{(aq)} \rightarrow Na_2SO_{4(aq)} + 2H_2O_{(l)}$; $H_2SO_{4(aq)} + NaOH_{(aq)} \rightarrow NaHSO_{4(aq)} + H_2O_{(l)}$ (Sodium hydrogensulphate)

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