<u>Answer:</u> The element represented by M is Strontium.
<u>Explanation:</u>
Let us consider the molar mass of metal be 'x'.
The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol
It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:

The metal atom having molar mass as 87.62/mol is Strontium.
Hence, the element represented by M is Strontium.
It will form a tetraamminezinc sulphate and a blue solution will be formed...the reaction should be carried out in a fume chamber because a poisonous substance will be released to the atmosphere
Answer and Explanation:
The equation that depicts oxidation of neutral atom A is shown below:

This is because one species is losing electrons due to oxidation. The species possesses positively charged after losing electrons, the magnitude of which is proportional to the number of electrons lost.
The net charge will be equivalent on both sides of the equation, too.
Therefore all other options are not correct
The equation that depicts the decline of neutral atom X is

It is how a cell gains electrons by reduction. The species obtains a negative charge upon possessing electrons, whose magnitude is equivalent to the amount of electrons gained.
The net charge will be equivalent on both sides of the equation, too.
Therefore all other options are not correct
There is this thing called isotopes
it means that atoms of the same element can have a different number of neutrons.
if there is a change in the no. of neutrons, there will definitely be a change in the mass number.
so the answer is A) mass number