Which of the following reactions are redox reactions?

Which of the following reactions are redox reactions? a. al(s)+3ag+(aq)→al3+(aq)+3ag(s) b. so3(g)+h2o(l)→h2so4(aq) c. ba(s)+cl2(g)→bacl2(s) d. mg(s)+br2(l)→mgbr2(s)

Answers

Options A, C and D.

Explanation:

Oxidation is the loss of electrons during a reaction by a molecule, atom or ion. It is represented by an increase in the oxidation number.

Reduction is the loss of electrons during a reaction by a molecule, atom or ion. It is represented by a decrease in the oxidation number.

Both processes makes up what we know as Redox (REDuction - OXidation) reactions.

Note: The oxidation number of an element in its ground state is 0.

To identify which reactions are redox, we look out for change in oxidation number of the molecule, atom or ions involved.

A) Al has an increase in oxidation number for 0 (reactant side) to +3 (product side), Silver moves from +1(reactant) to 0 (product side). this means Al was oxidized and Ag+ was reduced. This is a redox reaction.

B) All atoms involved retains their oxidation number. S= +6, O =-2, H =+1. This is not a redox reaction.

C) Ba has an increase in oxidation number form 0 to +2, while Cl has a decrease in oxidation number form 0 to -2. This is a redox reaction.

D) Mg has an increase in oxidation number form 0 to +2, while Br has a decrease in oxidation number form 0 to -2. This is a redox reaction.

SO3(g) + H2O(l) > H2SO4(aq)

Explanation:

'Redox' is a term used to describe reduction and oxidation since the both are complementary processes, one can not occur without the other.

A redox reaction is one in which there is a change in the oxidation number of the reactants from left to right of the reaction equation.

If we looks at the reaction;

SO3(g) + H2O(l) > H2SO4(aq)

There was no change in the oxidation numbers of species from left to right of the reaction equation. For instance, the oxidation state of sulphur is +6 on both sides of the reaction equation hence it is not a redox reaction.

a. Al(s)+3Ag+(aq)→Al3+(aq)+3Ag(s)

Al is the reducing agent and Ag is the oxidizing agent

c. Ba(s)+Cl2(g)→BaCl2(s)

Ba is the reducing agent and Cl2 is the oxidizing agent

d. Mg(s)+Br2(l)→MgBr2(s)

Mg is the reducing agent and Br2 is the oxidizing agent

If something loses electrons so its charge increases from Neutral (0) to +2. The substance that is oxidized is the reducing agent (causes the other to be reduced)

If it gains electrons the reduction is in the charge, which goes form neutral (0) to -1. (Since it is -1 you need 2 to balance the Mg+2). The substance that is reduced is the oxidizing agent (causes the other to be oxidized)

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts