Chapter 1 Chemical Reactions and Equations Solutions
Question - 11 : - What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer.
Answer - 11 : -
1. Hydrogen gas and Iron chloride are produced.
2. Chlorine gas and Iron hydroxide are produced.
3. No reaction takes place.
4. Iron salt and water are produced.
Answer
1. Hydrogen gas and Iron chloride are produced.
Explanation: The Chlorine from Hydrogen chloride is displaced by the Iron fillings to undergo the following reaction.
Answer - 12 : - A balanced equation is the one in which number of different atoms on both the reactant and product sides are equal. Balancing chemical equation is necessary for the reaction should obey The Law of Conservation of energy. Balancing the chemical equation has no defined method and is purely a trial and error attempt.
Question - 13 : - Translate the following statements into chemical equations and balance them.
Answer - 13 : -
(a) Hydrogen gas combines with nitrogen to form ammonia.
Answer (a)
Unbalanced: H2 + N2 → NH3
Balanced: 3H2 + N2 → 2NH3
(b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide.
Answer (b)
Unbalanced: H2S + O2 → H2O + SO2
Balanced: 2H2S + 3O2 → 2H2O + 2SO2
(c) Barium chloride reacts with aluminium sulphate to give Aluminium chloride and a precipitate of barium sulphate.
Answer (c)
Unbalanced: BaCl2 + Al2(SO4)3 → AlCl3 + BaSO4
Balanced: 3BaCl2 + Al2(SO4)3 → 2AlCl3 + 3BaSO4
(d) Potassium metal reacts with water to give potassium hydroxide and Hydrogen gas.
Answer (d)
Unbalanced: K + H2O → KOH + H2
Balanced: 2K + 2H2O → 2KOH + H2
Question - 14 : - Balance the following chemical equations.
Answer - 14 : -
(a) Unbalanced: HNO3 + Ca(OH)2 →Ca(NO3)2 + H2O
Balanced 2HNO3 + Ca(OH)2 →Ca(NO3)2 + 2H2O
(b) Unbalanced: NaOH + H2SO4 → Na2SO4 +H2O
Balanced 2NaOH + H2SO4 →Na2SO4 + 2H2O
(c) Unbalanced: NaCl + AgNO3 → AgCl + NaNO3
BalancedNaCl + AgNO3 → AgCl + NaNO3
(d) Unbalanced: BaCl2 + H2SO4 →BaSO4 + HCl
BalancedBaCl2 + H2SO4 → BaSO4 +2HCl
Question - 15 : - Write the balanced chemical equation for the following reactions.
Answer - 15 : -
(a) Calcium hydroxide + Carbon dioxide —-> Calcium carbonate + Water
2Ca(OH)2 + 2CO2 → 2CaCO3 +2H2O
(b) Zinc + Silver nitrate —-> Zinc nitrate + Silver
Zn + 2AgNO3 → Zn(NO3)2 +2Ag2Ag
(c) Aluminium + Copper chloride —-> Aluminium chloride + Copper
2Al + 3CuCl3 → 2AlCl3 + 3Cu
(d) Barium chloride + Potassium sulphate —-> Barium sulphate + Potassium chloride
BaCl2 + K2SO4 →BaSO4 + 2KCl
Answer - 16 : -
(a) Unbalanced KBr + BaI2 → KI + BaBr2
Balanced 2KBr + BaI2 → 2KI + BaBr2 (Double Displacement Reaction)
(b) Unbalanced ZnCO3 → ZnO + CO2
Balanced ZnCO3 → ZnO + CO2 (Decomposition Reaction)
(c) Unbalanced H2 + Cl → HCl
Balanced H2 + Cl → 2HCl (Combination Reaction)
(d) Unbalanced Mg + HCl → MgCl2 + H2
Balanced Mg + 2HCl → MgCl2 + H2 (Displacement Reaction)