Advertisements
Advertisements
प्रश्न
You are provided with two containers made up of copper and aluminium. You are also provided with solutions of dilute HCl, dilute HNO3, ZnCl2 and water. In which of the above containers, can these solutions be kept?
Advertisements
उत्तर
- Solutions to be kept in a copper container:
- Dilute HCl can be kept since no chemical reaction is expected. Copper is placed below hydrogen in the activity series.
- Dilute HNO3 cannot be kept since a chemical reaction is expected. Nitric acid is a strong oxidising agent.
\[\ce{3Cu_{(s)} + 8HNO_3_{(dil)} -> 3Cu(NO3)2_{(aq)} + 2NO_{(g)} + 4H2O_{(aq)}}\] - ZnCl2 solution can be kept since copper is placed below zinc in the activity series and no chemical reaction is possible.
- Water can be kept since no chemical reaction is expected.
- Solutions to be kept in an aluminium container:
- Dilute HCl cannot be kept since aluminium reacts with acid to evolve hydrogen gas.
\[\ce{2Al_{(s)} + 6HCl_{(aq)} -> 2AlCl3_{(aq)} + 3H2_{(g)}}\] - Dilute HNO3 can be kept. Actually, aluminium is initially oxidised by the acid to aluminium oxide (Al2O3). A coating of aluminium oxide gets deposited on the surface of the metal and makes it passive towards reaction with the acid.
- ZnCl2 solution cannot be kept since a chemical reaction will take place as aluminium is placed above zinc in the activity series.
\[\ce{2Al_{(s)} + 3ZnCl2_{(aq)} -> 2AlCl3_{(aq)} + 3Zn_{(s)}}\] - You can store water as such in the container. However, we cannot keep steam since a chemical reaction is likely to take place.
\[\ce{2Al_{(s)} + 3H2O_{(g)} -> Al2O3_{(s)} + 3H2_{(g)}}\]
- Dilute HCl cannot be kept since aluminium reacts with acid to evolve hydrogen gas.
APPEARS IN
संबंधित प्रश्न
What is an oxidation reaction? Identify in the following reaction (i) the substance oxidised, and (ii) the substance reduced:
ZnO + C → Zn + CO
In the following reaction between lead sulphide and hydrogen peroxide:
PbS (s) + 4H2O2(aq) → PbSO4(s) + 4H2O(1)
(a) which substance is reduced?
(b) Which substance is oxidised?
Fill in the blank
Oxidation is the removal of ......................and addition of ....................
Indicate which of the following statement is true and which is false:
The removal of hydrogen from a substance is called reduction.
Define an oxidation reaction.
Why this reaction is considered a reversible reaction?
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
H2S + Cl2→ 2HCl + S
Write the equation in the ionic form
CuSO4(aq) + Fe(s)→ FeSO4(aq) + Cu(s)
For the reaction PbO + H2→ Pb + H2O, which of the following statements is wrong?
With reference to oxidation & reduction reaction – complete the statement given by filling in the blanks with only the words (a) Addition (b) Removal.
‘Oxidation is a chemical reaction involving ____ of oxygen to a substance or ____ of hydrogen from a substance. Reduction on the otherhand involves ____ of hydrogen to a substance or ____ of oxygen from a substance.
Explain the following reaction with their balanced chemical equation.
Hydrogen sulphide reacts with sulphur dioxide.
Identify the following reactions as oxidation or reduction
- Na → Na+ + e
- Fe3+ + 2 e- → Fe+
Which of the following statements about the given reaction are correct?
\[\ce{3Fe_{(s)} + 4H2O_{(g)} -> Fe3O4_{(s)} + 4H2_{(g)}}\]
(i) Iron metal is getting oxidised.
(ii) Water is getting reduced.
(iii) Water is acting as the reducing agent.
(iv) Water is acting as oxidising agent.
Identify the reducing agent in the following reactions -
`"H"_2"O" + "F"_2 -> "HF" + "HOF"`
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
The temperature of the reaction mixture rises when aluminium (Al) is added.
Explain this observation giving suitable reason.
What happens when zinc granules are treated with dilute solution of H2SO4, HCl, HNO3, NaCl and NaOH Also write the chemical equations if reaction oçcurs.
Identify the following reactions as oxidation/reduction/redox reaction
2Mg +O2 → 2MgO
Find the oxidation number of the element in the following compound.
Zn in ZnSO4
State the change in colour observed in following case mentioning the reason:
Copper powder is strongly heated in air.
The oxidizing agent in the equation \[\ce{S + 2H2SO4 -> 3SO2 + 2H2O}\] is ______.
