Which of the following is not a physical change?
Boiling of water to give water vapour
Melting of ice to give water
Dissolution of salt in water
Combustion of Liquefied Petroleum Gas (LPG)
2. The following reaction is an example of:
\(4NH_3(g) + 5O_2(g) \to 4NO(g) + 6H_2O(g)\)
(i) displacement reaction
(ii) combination reaction
(iii) redox reaction
(iv) neutralisation reaction
(i) and (iv)
(ii) and (iii)
(i) and (iii)
(iii) and (iv)
3. Which of the following statements about the given reaction are correct?
\(3Fe(s) + 4H_2O(g) \to Fe_3O_4(s) + 4H_2(g)\)
(i) Iron metal is getting oxidised
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as oxidising agent
(i), (ii) and (iii)
(iii) and (iv)
(i), (ii) and (iv)
(ii) and (iv)
Which of the following are exothermic processes?
(i) Reaction of water with quick lime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals)
(i) and (ii)
(ii) and (iii)
(i) and (iv)
(iii) and (iv)
Three beakers labelled A, B and C each containing 25 mL of water were taken. NaOH, CuSO4 and NaCl were added to A, B and C respectively. Temperature increased in A and B, but decreased in C. Which statement(s) is/are correct?
(i) In beakers A and B, exothermic process has occurred.
(ii) In beakers A and B, endothermic process has occurred.
(iii) In beaker C, exothermic process has occurred.
(iv) In beaker C, endothermic process has occurred.
(i) only
(ii) only
(i) and (iv)
(ii) and (iii)
A dilute ferrous sulphate solution is added to acidified KMnO4. The purple colour fades and disappears. Which is the correct explanation?
KMnO4 is an oxidising agent; it oxidises FeSO4.
FeSO4 acts as an oxidising agent and oxidises KMnO4.
Colour disappears due to dilution; no reaction.
KMnO4 decomposes in presence of FeSO4 to a colourless compound.
Which among the following is/are double displacement reaction(s)?
(i) Pb + CuCl2 → PbCl2 + Cu
(ii) Na2SO4 + BaCl2 → BaSO4 + 2NaCl
(iii) C + O2 → CO2
(iv) CH4 + 2O2 → CO2 + 2H2O
(i) and (iv)
(ii) only
(i) and (ii)
(iii) and (iv)
Exposure of AgCl to sunlight turns it grey due to
(i) formation of silver by decomposition of AgCl
(ii) sublimation of silver chloride
(iii) decomposition with release of chlorine gas from AgCl
(iv) oxidation of silver chloride
(i) only
(i) and (iii)
(ii) and (iii)
(iv) only
Slaking of lime: \(CaO + H_2O → Ca(OH)_2 + \text{heat}\). Which is/are true?
(i) Endothermic reaction
(ii) Exothermic reaction
(iii) pH of solution > 7
(iv) pH of solution < 7
(i) and (ii)
(ii) and (iii)
(i) and (iv)
(iii) and (iv)
BaCl2 + (NH4)2SO4 → BaSO4(s) + 2NH4Cl. This reaction is
(i) Displacement (ii) Precipitation (iii) Combination (iv) Double displacement
(i) only
(ii) only
(iv) only
(ii) and (iv)
In electrolysis of water (a decomposition reaction), the mole ratio of hydrogen and oxygen gases liberated is
1 : 1
2 : 1
4 : 1
1 : 2
Which is/are endothermic process(es)?
(i) Dilution of sulphuric acid (ii) Sublimation of dry ice (iii) Condensation of water vapours (iv) Evaporation of water
(i) and (iii)
(ii) only
(iii) only
(ii) and (iv)
For the yellow ppt of PbI2 in a double displacement reaction with KI, if Pb(NO3)2 is unavailable, which can replace it?
Lead sulphate (insoluble)
Lead acetate
Ammonium nitrate
Potassium sulphate
Which gases can be used to store a fresh oil sample for long time?
CO2 or O2
N2 or O2
CO2 or He
He or N2
Preparation of oxygen in lab: \(2KClO_3(s) \xrightarrow[\text{catalyst}]{\text{Heat}} 2KCl(s) + 3O_2(g)\). Which statement(s) is/are correct?
Decomposition reaction and endothermic in nature
Combination reaction
Decomposition reaction accompanied by release of heat
Photochemical decomposition and exothermic
Which process involves a chemical reaction?
Storing O2 at high pressure in a cylinder
Liquefaction of air
Keeping petrol in an open dish
Heating copper wire in air at high temperature
Which equation correctly shows states at reaction temperature?
(a) \(2H_2(l)+O_2(l)→2H_2O(g)\) (b) \(2H_2(g)+O_2(l)→2H_2O(l)\) (c) \(2H_2(g)+O_2(g)→2H_2O(l)\) (d) \(2H_2(g)+O_2(g)→2H_2O(g)\)
(a)
(b)
(c)
(d)
Which of the following are combination reactions?
(i) \(2KClO_3 \xrightarrow{\text{Heat}} 2KCl + 3O_2\)
(ii) \(MgO + H_2O → Mg(OH)_2\)
(iii) \(4Al + 3O_2 → 2Al_2O_3\)
(iv) \(Zn + FeSO_4 → ZnSO_4 + Fe\)
(i) and (iii)
(iii) and (iv)
(ii) and (iv)
(ii) and (iii)