Chemical Reactions & Equations

Magnesium ribbon is rubbed before burning because it has a coating of

• basic magnesium carbonate

• basic magnesium oxide

• basic magnesium sulphide

• basic magnesium chloride

Calcium oxide reacts vigorously with water to produced slaked lime

CaO + H2O ---> Ca(OH)2

• Combination reaction

• Exothermic reaction

• Endothermic reaction

• Combination & Exothermic

• Combination & Endothermic

Which of the following displacement reaction?

• MgCo3 ---> MgO + CO2

• 2H2 + 2H2O ---> 2H2O

• 2Na + 2H2O ---> 2NaOH + H2

• 2Pb(NO3)2 ---> 2PbO + 4NO2 + O2

When green color ferrous sulphate crystals are heated, the color of crystal changes because

• loses water of crystalline

• decomposed to ferric oxide

• forms SO2

• forms SO3

A dil. ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple color of the solution fades and finally disappears. Which of the following is the correct explanation?

• KMnO4 is an oxidizing agent, it oxides FeSO4

• FeSO4 is an oxidizing agent, it oxides KMnO4

• Color disappears due to dilution, no reaction involved

• KMnO4 is an unstable compound and decomposes in the presence of FeSO4 to a colorless compund

When SO2 gas passed through saturated solution of H2S, which of the following reaction occurs?

• SO2 + 2H2S ---> 2H2O + 3S

• SO2 + 2H2S ---> H2O + 3S

• SO2 + H2S ---> H2O + S

• SO2 + H2O ---> H2 + SO3

A substance X is used in white - washing and is obtained by heating limestone in the absence of air. Identify X

• Cao

• CaCO3

• CaOCl2

• Ca(OH)2

MnO2 + 4 HCl ---> MnCl2 + 2H2O + Cl2

Identify the substances oxidized in the above reaction/equation

• MnCl2

• HCl

• H2O

• MnO2

Which of the following is the exothermic reaction?

i. Reaction of water with quick lime.

ii. Dilution of an acid

iii. Evaporation of water

iv. Sublimation of camphor

• i & iv

• ii & iv

• i & ii

• ii & iii

Which of the following statement about the reaction are correct?

3Fe + 4H2O ---> Fe2O4 + 4H2

i. iron metal getting oxidized

ii. Water is getting oxidized

iii. Water is acting as reducing agent

iv. Water is acting as oxidizing agent

• i, ii, iii

• iii, iv

• i, ii, iv

• ii , iv