Advertisements
Advertisements
Question
How do you count for the following observations?
When concentrated sulphuric acid is added to an inorganic mixture containing chloride, we get colourless pungent-smelling gas HCl, but if the mixture contains bromide then we get red vapour of bromine. Why?
Advertisements
Solution
When conc. H2SO4 is added to an inorganic mixture containing bromide, initially HBr is produced. HBr, being a strong reducing agent reduces H2SO4 to SO2 with the evolution of red vapour of bromine.
\[\ce{2NaBr + 2H_2SO_4 -> 2NaHSO_4 + 2HBr}\]
\[\ce{2HBr + H_2SO_4 -> \underset{red vapour}{Br_2 + SO_2} + 2H_2O}\]
But, when conc. H2SO4 is added to an inorganic mixture containing chloride, a pungent smelling gas (HCl) is evolved. HCl, being a weak reducing agent, cannot reduce H2SO4 to SO2.
\[\ce{2NaCl + 2H_2SO_4 -> 2NaHSO_4 + 2HCl}\]
APPEARS IN
RELATED QUESTIONS
Justify that the following reaction is redox reaction:
\[\ce{CuO(s) + H2(g) → Cu(s) + H2O(g)}\]
Justify that the following reaction is redox reaction:
\[\ce{2K(s) + F2(g) → 2K+F– (s)}\]
While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?
Identify the substance oxidised, reduced, oxidising agent and reducing agent for the following reaction:
\[\ce{N2H4(l) + 2H2O2(l) → N2(g) + 4H2O(l)}\]
Consider the reactions:
\[\ce{2S_2O_3^{(2-)}(aq) + l_2(S) -> S_4O_6^{(2-)}(aq) + 2l-(aq)}\]
\[\ce{S_2O_3^{(2-)}(aq) + 2Br_2(l) + 5H_2O(l) -> 2SO_4^{2-} (aq) + 4Br-(aq) + 10H+ (aq)}\]
Why does the same reductant, thiosulphate react differently with iodine and bromine?
Refer to the periodic table given in your book and now answer the following question:
Select three metals that can show disproportionation reaction.
Which of the following is not an example of redox reaction?
Identify disproportionation reaction
Which of the following elements does not show disproportionation tendency?
Assertion (A): Redox couple is the combination of oxidised and reduced form of a substance involved in an oxidation or reduction half cell.
Reason (R): In the representation \[\ce{E^Θ_{Fe^{3+}/Fe^{2+}}}\] and \[\ce{E^Θ_{Cu^{2+}/Cu}, Fe^{3+}/Fe^{2+}}\] and \[\ce{Cu^{2+}/Cu}\] are redox couples.
Why does fluorine not show disporportionation reaction?
Write redox couples involved in the reactions given.
\[\ce{Cu + Zn^{2+} ->Cu^{2+} + Zn}\]
Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine.
\[\ce{NaClO4, NaClO3, NaClO, KClO2, Cl2O7, ClO3, Cl2O, NaCl, Cl2 , ClO2}\].
Which oxidation state is not present in any of the above compounds?
Which of the following examples does not represent disproportionation?
Which of the following reactions is the metal displacement reaction? Choose the right option.
An acidified manganate solution undergoes disproportionation reaction. The spin-only magnetic moment value of the product having manganese in a higher oxidation state is ______ B.M. (Nearest integer)
The species given below that does NOT show a disproportionation reaction is ______.
