Questions
Short answer type
1. Define the following terms
i. Combination reaction
ii. Decomposition reaction
iii. Double decomposition reaction
iv. Neutralisation reaction
v. Displacement reaction
vi. Redox reaction
2. Give one example each of the following
i. electrolytic decomposition, ii. thermal decomposition, iii. photo decomposition
3. Classify the following reactions into oxidation and reduction reactions
i. 2 CO + O2 → 2 CO2 ii. 2 HI → H2 + I2 iii. N2 + 3 H2 → 2 NH3 iv. 2 BaO2 → 2 BaO + O2
4. Give one example each of a fast and slow chemical reaction.
5. What is a catalyst ? What is its function ?
Long answer type
1. What is activity series of metals ? How is it formed ? What is its use ?
2. Explain any two factors which affect the rate of a chemical reaction.
3. Give any five examples of catalysts used in industrial processes.
4. Give two examples to show that the same reaction can be classified under two headings. Justify your answer.
Give reasons for the following
1. Solutions of silver salts are kept in amber coloured bottles
2. Patients suffering from acidity are given antacids.
3. Hydrogen peroxide bottle is always kept in a refrigerator.
4. Purple colour of potassium permanganate is discharged on addition of lemon juice.
5. Iron pan becomes reddish brown after long use.
Fill in the blanks
1. Heating white phosphorus in air is a —reaction.
2. Reaction between sodium metal and water to give hydrogen gas is a —re- action.
3. A catalyst —the rate of a chemical reaction.
4. Unless there is oxidation, there can not be reduction. So oxidation and reduction reactions take place —
5. A reaction in which radicals mutually exchange their positions to form new compound is called —reaction.
State whether true or false
1. Decomposition reactions are also called displacement reactions.
2. The product formed by the combination of ammonia gas and hydrochloric acid is gaseous.
3. Decomposition of potassium chlorate takes place quicker in presence of a catalyst.
4. Silver bromide, when exposed to sunlight, gets converted to silver and bromine. This is an example of thermal decomposition reaction.
5. Every neutralization reaction is a double decomposition reaction.
Match the following
Multiple choice questions
1. Which of the following is a displacement reaction
a. Mg(HCO3)2 → MgCO3 + CO2 + H2O b. Mg + 2 HCl → MgCl2 + H2 c. 2 Zn + O2 → 2 ZnO d. 2 KClO3 → 2 KCl + 3 O2
2. Which of the following is a double decomposition reaction ?
a. CaO + H2O → Ca(OH)2 b. Zn + CuSO4 → ZnSO4 + Cu c. H2 O2 + 2 KI → 2 KOH + I2 d. ZnSO4 + H2S → ZnS + H2 SO4
3. Which of the following factors can not affect the rate of a reaction taking place in aqueous medium ?
a. temperature
b. pressure
c. concentration
d. catalyst
4. Which of the following reactions can be classified under two types?
a. NaOH + HCl → NaCl + H2O
b. H2 O2 + 2 KI → 2 KOH + I2
c. 3 Cu + 2 AuCl3 → 2 Au + 3 CuCl2
d. N2 + 3 H2 → 2 NH3
5. At certain temperature, two elements react to form a compound. This compound decomposes at higher temperature to form the original two elements. Such a reaction is called —–
a. homogeneous reaction
b. exothermic reaction
c. reversible reaction
d. decomposition reaction
Answers –1) b 2) d 3) b 4) a 5) c
More difficult questions
1. Which of the following factors will affect the most, the rate of following reaction ? H2 (g) + Cl2 (g) → 2 HCl (g)
a. particle size, b. concentration, c. pressure, d. catalyst
2. Which of the following reactions can be classified under two headings ?
a. KBr + NaCl → KCl + NaBr b. PbCl2 + 2 KI → PbI2 + 2 KCl c. 2 KOH + H2 SO4 → K2 SO4 + 2 H2O d. NH4Cl + NaOH → NaCl + NH4OH
3. Which of the following is not a displacement reaction ?
a. 2 Na + 2 H2O → 2 NaOH + H2 b. Mg + H2 SO4 → MgSO4 + H2 c. Sn + 2 HNO3 → Sn(NO3)2 + H2 d. Zn + 2 NaOH → Na2 ZnO2 + H2
4. Which of the following is a redox reaction ?
a. BaCl2 + H2 SO4 → BaSO4 + 2 HCl b. Pb(NO3)2 + 2 KI → PbI2 + 2 KNO3 c. PbO + H2 O2 → PbO2 + H2O d. H2 C2 O4+ 2 KOH → K2 C2 O4 + 2 H2O
5. Which of the following reactions is a ’decomposition reaction’ as well as a ’redox reaction’.
a. 2 KClO3 → 2 KCl + 3 O2 b. CaCO3 → CaO + CO2 c. NH4Cl → NH3 + HCl d. H2 SO4 → H2O + SO3
Answers –1) b 2) c 3) d 4) c 5) a