In which of the following substances will there be :

(a) increase in mass

(b) decrease in mass

(c) no change in mass when they are exposed to air?

1. Sodium chloride

2. Iron

3. Conc. sulphuric acid

4. Table salt

5. Sodium carbonate crystals

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Solution

(a) Increase in mass - Iron and conc. sulphuric acid.
(b) Decrease in mass - Sodium carbonate crystals.
(c) No change in mass - Sodium chloride.

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Similar questions

State whether a sample of each of the following would increase or decrease in mass if exposed to air.

(a) Solid NaOH, (b) Solid $C a C l_{2}$ ,

(e) Iron (III) Chloride

Choosing the substances from the list given below, write balanced chemical equations for the reaction which would be used in the laboratory to obtain the following salts.

[Dilute sulphuric acid, Copper, Copper(II) carbonate, Iron, Sodium carbonate, Sodium chloride, Zinc nitrate]

Zinc carbonate salt :

Give reasons for the following:
(i) In the contact process, sulphur trioxide formed is dissolved in 98% sulphuric acid and not in water.
(ii) When solution of sulphur dioxide is exposed to air, it gets converted to sulphuric acid.
(iii) When diluting concentrated sulphuric acid, the acid should be added to water and not water to the acid.
(iv) When concentrated sulphuric acid is exposed to air, its volume increases and it becomes slightly dilute.
(v) Sulphuric acid can form two kinds of salts with sodium chloride.
(vi) When barium chloride is added to dilute sulphuric acid, a white precipitate is formed.
(vii) When carbon is heated with concentrated sulphuric acid, carbon dioxide is formed.
(viii) Ammonia gas cannot be dried by passing through concentrated sulphuric acid.
(ix) When concentrated sulphuric acid is added to sugar/glucose, a black mass is left behind.
(x) Concentrated sulphuric acid should not be added to oxalic acid or formic acid in the open laboratory.
(xi) When concentrated sulphuric acid is added to blue crystalline copper sulphate, it turns powdery white.
(xii) Concentrated sulphuric acid must be stored in airtight bottles.
(xiii) Cotton clothes get burnt with concentrated sulphuric acid.
(xiv) H₂SO₄ cannot be prepared by heating sodium sulphate with conc. HCl or HNO₃.

Q. (a) Choosing only substances from the list given in the box below, write equations for the reactions which you would use in the laboratory to obtain:
(i) Sodium sulphate
(ii) Copper sulphate
(iii) Iron (II) sulphate
(iv) Zinc carbonate

Dilute sulphuric acid

Copper
Iron
Sodium, Zinc

Copper carbonate
Sodium carbonate

(b) From the formulae listed below, choose one, in each case, corresponding to the salt having the given description:
AgCl, CuCO₃, CuSO₄·5H₂O, KNO₃, NaCl, NaHSO₄, Pb(NO₃)₂, ZnCO₃, ZnSO₄·7H₂O.
(i) An acid salt.
(ii) An insoluble chloride.
(iii) On treating with concentrated sulphuric acid, this salt changes from blue to white.
(iv) On heating this salt changes from green to black.
(v) This salt gives nitrogen dioxide on heating.

(b) From the list of substances given below, choose the pair required to prepare the salts (i) to (iii) in the laboratory and write down the relevant equations. The substances are
chlorine, iron, lead, lead nitrate solution, sodium nitrate solution, iron (III) carbonate, lead carbonate, iron (III) hydroxide, sodium hydroxide solution and dilute hydrochloric acid. The salts are
(i) sodium chloride.
(ii) lead chloride.
(iii) anhydrous iron (III) chloride.

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In which of the following substances will there be : (a) increase in mass (b) decrease in mass (c) no change in mass when they are exposed to air? 1. Sodium chloride 2. Iron 3. Conc. sulphuric acid 4. Table salt 5. Sodium carbonate crystals

(a) Increase in mass - Iron and conc. sulphuric acid. (b) Decrease in mass - Sodium carbonate crystals. (c) No change in mass - Sodium chloride.

In which of the following substances will there be :

(a) increase in mass

(b) decrease in mass

(c) no change in mass when they are exposed to air?

1. Sodium chloride

2. Iron

3. Conc. sulphuric acid

4. Table salt

5. Sodium carbonate crystals

(a) Increase in mass - Iron and conc. sulphuric acid.
(b) Decrease in mass - Sodium carbonate crystals.
(c) No change in mass - Sodium chloride.