Look at the reaction below. Upper H subscript 2 upper S upper O subscript 4 (a q) plus upper Upper M g (s) right arrow Uper M g upper S upper O subscript 4 (a q) plus upper H subscript 2 (g). Which substance is the acid in the reaction? Mg(s) H2(g) MgSO4(aq) H2SO4(aq)

H2SO4(aq)

Explanation:

The balanced equation for the reaction is given below:

H2SO4(aq) + Mg(s) —> MgSO4(aq) + H2 (g)

An acid is a substance which dissolves in water to produce hydrogen ion, H+ as the only positive ion.

To know which of the substance is acid, let us dissolve them in water to see which will produce hydrogen ion, H+ as the only positive ion.

This is illustrated below:

H2SO4(aq) —> 2H+(aq) + SO4^2-(aq)

Mg(s) + 2H2O(l) —> Mg(OH)2(aq) + H2(g)

MgSO4(aq) —> Mg^2+(aq) + SO4^2-(aq)

H2 is insoluble in water.

From the above, only H2SO4 produces hydrogen ion H+ on dissolution in water. Therefore, H2SO4 is an acid

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms