Question

(c) Match the types of chemical reaction provided in the following list with each of the chemical
equations from (i) to (y)
[ Precipitation reaction, neutralization reaction, combination reaction, decomposition
reaction or displacement reaction]
[5]
(1)
2HI,O 2 H+ O,
(11)
NH, + HCI → NHCl
CuCG + Pb > PbCl2 + Cu
(iv)
Ca ( OH )2+ 2 HC1） Ca Cl, + H,O
(v)
2 KI+ Pb (NO ) 2 KNO+ Pb I2​

Answer 1

Answer:

i.) 2H₂O → 2H₂ + O₂ ➝ Decomposition

ecompositionreaction

Explanation:

Here, the decomposition of compound 'water' occurs by electrolysis of acidified water in the presence of electricity to give hydrogen and oxygen. So, here water decomposes into hydrogen and oxygen. Thus, it is a decomposition reaction.

ii.) NH₃ + HCl → NH₄Cl ➝ Combination reaction

Explanation:

Here, ammonia and hydrogen chloride, both compounds combine to form new compound, ammonium chloride. So two or more compounds combine to form a single product. Thus, it is a direct combination or synthesis reaction.

iii.) CuCl₂ + Pb → PbCl₂ + Cu ➝ Displacement reaction

Explanation:

Here, lead it displaces copper from its salt solution because lead is more reactive than copper. The more reactive element displaces the less reactive element from its salt solution. Thus, it is a displacement reaction.

iv.) Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂O ➝ Neutralization reaction

Explanation:

The reaction takes place because the hydrogen (H⁺) ion from the acid combines with the hydroxyl ion (OH⁻) from the base to form water. So, the reaction is between a acid and a base. Thus, it is a neutralization reaction.

v.) 2KI + Pb (NO₃)₂ → 2KNO₃ + PbI₂ ➝ Precipitation reaction

Explanation:

Here, potassium iodide (white) and lead nitrate (white) react to make yellow insoluble substance (precipitate) lead iodide. So it is a chemical reaction in which formation of insoluble solid substance called precipitate occurs. Thus, it is a precipitation reaction.

_______________________________