NECO GCE 2021 CHEMISTRY ESSAY AND OBJ ANSWERS

Chemistry Paper III & II (Objective & Essay)

2bii ) *DIFFERENCE BETWEEN ELECTROVALENT BOND AND COVALENT BOND*

Electrovalent bond is characterised by transfer of electrons from metallic atoms to non metallic atoms during a chemical reaction i.e donor – acceptor principle.

Covalent bonding , electrons are not transferred but shared.
5ai)) Empirical formula is the formula which gives the simple whole number ratio of the atom of various elements present in one molecule of the compound while molecular formula gives the actual number of atoms of various elements present in one molecule of the compound.

No1)
1ai) Provision of employment

ii) Production of building materials such as cement, paint etc. For good standard of living

iii) Improvement of social well being of the people

1aii) HCI is oxidized because oxidation is the removal of hydrogen atom from a compound

6a)
Explanation: When the collection of sap is over, fermentation sets in immediately, and the sap is converted into fresh coconut palm wine or sweet toddy. This product is a milky white and effervescent liquid. Fermentation continues for few more hours after the sap has been pooled from various pots.
1bi ) Weak electrolyte are the electrolytes that are partially ionized in water
Inert electrolytes : This is a metal submerged in an aqueous solution if ion compound that eventually transfer electrons rather than donating or exchanging ions with the aqeous solutions
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PROPERTIES OF HALOGEN
1. They are all composed of covalent molecules containing two atoms X² i.e diatomic molecules where X is an halogen.

2. All halogens dissolve to some extent in water , fluorine reacts vigorously and completely in water to give oxygen and hydrogen fluoride…