Everything Science Grade 11

CHAPTER 8. TYPES OFREACTIONS 8.3

iii. O 2

(b) Does the hydrogen peroxide (H 2 O 2 ) act as an oxidising agent or a reducing agent or both,

in the above reaction? Give a reason for your answer.

2. Consider the following chemical equations:
   
   
   1. Fe(s)→ Fe2+(aq) + 2e−
   
   
   2. 4 H+(aq) + O 2 (g) + 4e−→ 2 H 2 O(�)
   
   
   
   

Which one of the following statements is correct?

(a) Fe is oxidised and H+is reduced

(b) Fe is reduced and O 2 is oxidised

(c) Fe is oxidised and O 2 is reduced

(d) Fe is reduced and H+is oxidised

(DoE Grade 11 Paper 2,2007)

3. Which one of the following reactions is a redox reaction?

(a) HCl + NaOH→ NaCl + H 2 O

(b) AgNO 3 + NaI→ AgI + NaNO 3

(c) 2FeCl 3 + 2H 2 O + SO 2 → H 2 SO 4 + 2HCl + 2FeCl 2

(d) BaCl 2 + MgSO 4 → MgCl 2 + BaSO 4

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8.3 Addition, substitution and elimination reactions

ESBCD

Addition reactions ESBCE

An addition reaction occurs when two or more reactants combine to forma final product. This product

will contain all the atoms that were present in the reactants. The following is a general equation for

this type of reaction:

A + B→ C

Notice that C is the final product with no A or Bremaining as a residue.

The following are someexamples.

1. The reaction between ethene and bromine to form 1,2-dibromoethane (Figure 8.1).

C 2 H 4 + Br 2 → C 2 H 4 Br 2