రసాయన చర్యలు మరియు సమీకరణాలు, Chemical Reactions and Equations Notes

1. Which of the statements about the reaction below are incorrect?
2PbO(s) + C(s)→ 2Pb(s) + CO2(g)
(a)Lead is getting reduced. (b)Carbon dioxide is getting oxidised. (c)Carbon is getting oxidised. (d)Lead oxide is getting reduced. (i)(a) and (b) (ii)(a) and (c) (iii) (a), (b) and (c) (iv) all
A. The statements about the reaction following are incorrect (i)(a) and (b)
(a)Lead is getting reduced and (b)Carbon dioxide is getting oxidised. 2. Fe2O3 + 2Al→ Al2O3 + 2Fe The above reaction is an example of a
(a) Combination reaction. (b) Double displacement reaction. (c) Decomposition reaction. (d) Displacement reaction. A. (d) displacement reaction. 3. What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer. (a)Hydrogen gas and iron chloride are produced. (b)Chlorine gas and iron hydroxide are produced. (c) No reaction takes place. (d)Iron salt and water are produced. A. (a) Hydrogen gas and iron chloride are produce
4. What is a balanced chemical equation? Why should chemical equations be balanced?
A. (i) When the total number of atoms of each element is same on both sides in a chemical equation, then the chemical equation is said to be a balanced chemical equation. Ex: Mg + H2SO4 →MgSO4 + H2
(ii) Chemical equation must follow the law of conservation of mass. (iii) So the chemical equation should be balanced. (iv) Then only they can follow the law of conservation of mass. 5. Translate the following statements into chemical equations and then balance them. (a) Hydrogen gas combines with nitrogen to form ammonia. A. (a) Skeletal equation:
H₂ (g) + N₂(g) →NH₃(g)
Balanced equation:
3H₂ (g)+ N₂(g) →2NH₃(g)
(b) Hydrogen sulphide gas burns in air to give water and sulpur dioxide. A. (b) Skeletal equation:
H₂S (g) + O₂(g) → H₂O (l) + SO₂(g)
Balanced equation:
2H₂S(g) + 3O₂ (g) → 2H₂O(l) + 2SO₂(g)
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of
barium sulphate. A. (c) Skeletal equation:
BaCl₂(aq) + Al₂SO₄(aq) → AlCl₃(aq) + BaSO₄(s)
Balanced equation:
3BaCl₂(aq) + Al₂(SO₄)₃(aq) → 2AlCl₃(aq) + 3BaSO₄(s)
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas. A. (d) Skeletal equation:
K(s) + H₂O(l) → KOH(aq) + H₂(g)
Balanced equation:
2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g)
7. Write the balanced chemical equations for the following reactions. (a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water
A. Ca(OH)2 + CO2 →CaCO3 + H2O
(b) Zinc + Silver nitrate → Zinc nitrate + Silver
A. Zn + 2AgNO3→ Zn(NO3)2 + 2Ag
(c) Aluminium + Copper chloride → Aluminium chloride + Copper
A. 2Al + 3CuCl2 →2AlCl3 + 3Cu
(d) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride
A. BaCl22+ K2SO4→BaSO4 + 2KCl
8. Write the balanced chemical equation for the following and identify the type of reaction in each
case. (a) Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)
A. 2KBr(aq)+ BaI2 (aq)→2KI(aq)+ BaBr2 (s