Question

(class 10) Subject=Science....​

Answer 1

Explanation:

1.) 1. Oxides of group first = E20

• As group first elements have only one electron in its valence shell and valency of oxygen is 2.

2. Halides of group Thirteen = EX3

• As group thirteen elements have three electron in its valence shell and valency of halogens is 1.

3. Compound formed by A & B = AB2

• Element A belongs to group second so its valency is two and element B belongs to group seventeen so its valency 1.

2.) 1. Zn (s) + 2 NaOH (aq) -------> Na2 Zn O2 (aq) + H2 (g)

2.Gas evolve is hydrogen and when burning candle is bring near the test tube it burns with a pop sound.

3. When same metal i.e. Zn react with dil. acid then same gas i.e. Hydrogen gas is evolved

Answer 2

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