Zinc dissolves in hydrochloric acid to yield hydrogen gas: zn(s) + 2hcl(aq) → zncl2(aq) + h2(g) when a 12.7 g chunk of zinc dissolves in 500. ml of 1.450 m hcl, what is the concentration of hydrogen ions remaining in the final solution?

First calculate the initial moles of HCl.

HCl moles i = (1.45 moles / L) * 0.5 L = 0.725 moles HCl

Then calculate how much HCl is consumed by stoichiometry:

HCl moles consumed = (12.7 g Zn / 65.38 g / mol) * (2 moles HCl / 1 mole Zn) = 0.388 moles

So HCl moles left is:

HCl moles f = 0.725 – 0.388 = 0.3365 moles

For every 1 mole HCl there is 1 mole H, therefore:

H moles final = 0.3365 moles

So final concentration of H ions is:

Concentration H = 0.3365 moles / 0.5 L = 0.673 M

- 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