NECO 2021 CHEMISTRY VERIFIED

Here is the neco chemistry answers 2021… Make sure you share to your friends make everyone pass

(1a)

-High temperature is required

-High pressure

-The presence of Catalyst

(1b)

(i) To avoid corrosion

(ii) To avoid rusting

(1ci)

Calcium oxide (CaO) is alkaline and Hcl is acidic. The two react to form calcium chloride and water; instead of dry Hcl, after that, it will end up with wet calcium chloride.

(1cii)

Concentrated H2SO4(aq)

(1d)

Conc HNO3(aq) reacts with a solution of FeSO4(aq). The Fe2+ was oxidised to yellow Fe3+ and brown NO2(g) was given off.

ie 2HNO3(aq) + 2FeSO4(aq) + H2SO4 -> Fe2(SO4)3 + 2NO2(g) + 2H2O

(1ei)

(I) ZnO(s) + H2SO4(aq) —> ZnSO4(aq) + H2O(l)

(II) ZnO(s) + NaOH(aq) —> Na2ZnO2(s) + H2O

1ei)

(I) ZnO(s) + H2SO4(aq) —> ZnSO4(aq) + H2O(l)

(II) ZnO(s) + NaOH(aq) —> Na2ZnO2(s) + H2O(l)

(1eii)

(III) Amphoteric property

(1f)

(i) They have the same number of atoms

(ii) They have different neutron number which makes their mass number to differ

(1g)

HclO – Oxochlorate(i)acid and Hcl

(1hi)

H2S is undergoing oxidation to S(s)

(1hii) loading……

2b

I.. Activation energy is the minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction.

2ci

Chemical Properties of Ethanoic Acid (Reactions of Ethanoic Acid)

A. *Esterification Reaction*: When any carboxylic acid reacts with any alcohol, it leads to the formation of another class of chemical compounds named esters. This reaction which leads to the formation of esters is known as esterification reaction. Given below is an example presented when the Ethanoic Acid (a carboxylic acid) reacts with Ethanol (ethyl alcohol) resulting in the formation of ethyl ethanoate (an ester):

CH3COOH + CH3CH2OH → CH3COOCH2CH3

(Ethanoic acid) (Ethanol) (Ethyl Ethanoate)

The new class of chemical compounds formed by this reaction (Esters) has a characteristic fruity smell by which they can be easily identified. Esters are commercially used as synthetic flavouring agents in the food industry and for their good fragrance in the perfume industry. Apart from this, one of the main uses of esters is in the production of soaps. When esters are reacted with any base (particularly alkalis), they give a carboxylic acid salt which is the basic molecular structure of soaps. This reaction is known as saponification reaction. Higher molecular weight esters are generally preferred to carry out this reaction. A general elucidation of a saponification reaction is given below:

RCOOR’ + NaOH → RCOO–Na+ + R’OH

(An ester) (Sodium hydroxide) (Soap) (Alcohol)

B. *Reaction with Base*: Ethanoic Acid is a weak acid. Like any acid, it reacts with a base to form one molecule of salt and one molecule of