On the reaction 2Ag + 2H₂SO₄ \(\rightarrow\) Ag₂So₄ + 2H₂O+S_O2  sulphuric acid acts as ______.

When methane is burnt in oxygen to produce CO₂ and H₂0 the oxidation number of carbon changes by ______.

Which of the following are not redox reactions?

Which one among the following is not example of autoredox reaction?

In the ethylene molecule the two carbon atoms have the oxidation numbers.

Find the value of n in 4MnO₄^-+8H⁺ +ne^- \(\rightarrow\) Mn²⁺ +4H₂O

Does the oxidation number of an element in any molecule or any polyatomic ion represent the actual charge on it?

How would you know whether a redox reaction is taking place in an acidic, alkaline or netural medium?

Consider the reactions:
(a) H₃PO₂(aq) + 4 AgNO₃(aq) + 2 H₂O(l) → H₃PO₄(aq) + 4Ag(s) + 4HNO₃(aq)
(b) H₃PO₂(aq) + 2CuSO₄(aq) + 2 H₂O(l) → H₃PO₄(aq) + 2Cu(s) + H₂SO₄(aq)
(c) C₆H₅CHO(l) + 2[Ag (NH₃)₂]⁺(aq) + 3OH^–(aq) → C₆H₅COO^–(aq) + 2Ag(s) + 4NH₃ (aq) + 2 H₂O(l)
(d) C₆H₅CHO(l) + 2Cu²⁺⁽aq) + 5OH^–(aq) → No change observed.
What inference do you draw about the behaviour of Ag⁺ and Cu²⁺ from these reactions?

Arrange the following metals in the order in which they displace each other from the solution of their salts. Al, Cu, Fe, Mg and Zn.

In \({ MnO }_{ 4 }^{ 2- }\)  undergoes disproportionation reaction in acidic medium but\({ MnO }_{ 4 }^{ - }\)  does not. Give reason.

Consider the elements:Cs,Ne,I and F.
(a) Identify the element that exhibits only positive oxidation state.
(b) Identify the element that exhibits both positive and negative oxidation states.
(c) Identify the element which exhibits neither the negative nor does the positive oxidation state.

What is a standard hydrogen electrode?

One mole of N₂H₄ loses 10 moles electrons to form a new compound Y. Assuming that all the nitrogen appears in the new compound, what is the oxidation number of N in Y ? There is no change in oxidation state of H.

Identify the oxidant and reductant in the following redox reaction: 
2K₂MnO₄ + Cl₂ \(\rightarrow\) 2kcl + 2KMnO₄

Using the standard electrode potentials given in the predict if the reaction between the following is feasible - Ag⁺(aq) and Cu(s)

Justify that the reactions : 2Na(s)+H₂(g)\(\rightarrow \)2NaH(s) is a redoxchange.

Rahul was very angry because he got an oil spot on his favourite shirt. His mother want to make him happy but does not know what to do. Her neighbour Mrs. Sharma advised him to use bleach (bleaching powder, CaOCl₂) to remove the oil spot.
(i) Do you suggest the same thing to remove oil spot ? Why or why not ? Justify your answer.
(ii) What is the oxidation number of both the Cl-atoms in the bleaching powder?
(iii) Which substance, is available in the market to remove such spots?
(iv) What values are associated with Mrs. Sharma?

Justify that the following reaction are redox reaction
(a) \(CuO(s)+{ H }_{ 2 }(g)\rightarrow Cu(s)+{ H }_{ 2 }O(g)\)
(b) \({ F }e_{ 2 }O_{ 3 }(s)+3CO(g)\rightarrow 2Fe(s)+3{ CO }_{ 2 }(g)\)
(c) \(4BCl_{ 3 }(g)+3LiAl{ H }_{ 4 }(s)\longrightarrow 2{ B }_{ 2 }{ H }_{ 6 }(g)+3LiCl(s)+3AlC{ l }_{ 3 }(s)\)
(d) \(2k(s)+{ F }_{ 2 }(g)\longrightarrow 2K^{ + }{ F }^{ - }(s)\)
(e) \(4N{ H }_{ 3 }(g)+5{ O }_{ 2 }(g)\longrightarrow 4NO(g)+6H_{ 2 }O(g)\)

How do you count for the following observations ?
(a) Though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants, yet in the manufacture of benzoic acid from toluene we use alcoholic potassium permanganate as an oxidant. Why ? Write a balanced redox equation for the reaction.
(b) 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 ?