Answer:
high ph -basic,low pH -acidic
Explanation:
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Explanation:
12)
a) Sodium + oxygen = ?
When sodium reacts oxygen its forms sodium oxide as a product.

b) magnesium + fluorine = ?
When magnesium reacts with fluorine its forms magnesium fluoride as a product.

13)
a) 
Decomposition of mercury(II) oxide on heating gives out mercury and oxygen gas.
b)
The electrolytic decomposition of water gives out hydrogen gas amd oxygen gas.
Answer: 1Ca + 2O + 2H
Explanation:
Ca is 1 since there is no subscript
O and H each have 2 because the subscript 2 is outside the parenthesis so you multiply their subscript (1) by 2