Chemical Reactions Acids Bases and Salts (Class 10)

What this worksheet covers

This is an eighteen-question practice worksheet on chemical reactions, acids, bases and salts for Class 10, written to the pattern of the SOF National Science Olympiad (NSO). It carries 24 marks and is designed to be attempted in 45 minutes, split across three sections — Scientific Reasoning, Applying What You Know and Achievers Section. Every question is multiple choice with exactly one correct option, and every one comes with a fully worked solution rather than just an answer key — so a child who gets one wrong can see where the reasoning went astray instead of only learning that it did.

Skills your child practises

• Applied problem-solving on chemical reactions, acids, bases and salts at Class 10 level
• Working accurately against a time limit, as the real paper demands
• Scientific Reasoning questions in the olympiad format
• Applying What You Know questions in the olympiad format
• Achievers Section questions in the olympiad format
• Reading worked solutions to find the step that went wrong

How to use it

1. 1There are 18 questions in this worksheet. All questions are compulsory.
2. 2Each question has four options (A), (B), (C) and (D). Exactly one option is correct.
3. 3Questions 1–15 carry 1 mark each. Questions 16–18 (Achievers Section) carry 3 marks each.
4. 4There is no negative marking. Study every diagram and table carefully.

Sample questions from this worksheet

A preview of what's inside Chemical Reactions Acids Bases and Salts (Class 10) — the PDF has the full set, and every question comes with a worked solution like these.

1. 1. A chemical equation is balanced in order to satisfy the law of _______.

   • AConservation of energy
   • BConstant proportions
   • CConservation of masscorrect
   • DMultiple proportions
   Solution: Atoms are only rearranged in a reaction, never created or destroyed, so the same number of atoms of each element must appear on both sides. Balancing an equation is exactly what expresses the law of conservation of mass.

2. 2. Which of the following is a displacement reaction?

   • AFe + CuSO₄ → FeSO₄ + Cucorrect
   • BCaO + H₂O → Ca(OH)₂
   • CCaCO₃ → CaO + CO₂
   • DNaOH + HCl → NaCl + H₂O
   Solution: Iron is more reactive than copper, so it pushes copper out of its salt solution: Fe + CuSO₄ → FeSO₄ + Cu. The others are, in order, combination, decomposition and neutralisation reactions.

3. 3. In the reaction Zn + 2HCl → ZnCl₂ + H₂, which statement is correct?

   • AZinc is oxidised and hydrogen is reducedcorrect
   • BZinc is reduced and hydrogen is oxidised
   • CBoth zinc and hydrogen are oxidised
   • DIt is a double displacement reaction
   Solution: Zinc loses electrons to become Zn²⁺, so it is oxidised, while the hydrogen ions gain electrons to become hydrogen gas, so they are reduced. Hence zinc is oxidised and hydrogen is reduced. Zinc displacing hydrogen from the acid makes this a displacement, not a double displacement.