Tính pH của các dung dịch thu được trong mỗi thí nghiệm sau: a. Hòa tan hoàn toàn 3,65 g HCl vào nước thu được 1 lít dung dịch. b. Hòa tan hoàn toàn 4 g NaOH vào nước thu được 1 lít dung dịch. c. Hòa tan hoàn toàn một lượng H2SO4 vào nước, thu được 100 g dung dịch H2SO4 4,9%. (V = 1 lít). d. Hòa tan hoàn toàn một lượng Ba(OH2) vào nước, thu được 200 g dung dịch Ba(OH2) 1,71%. (V = 1 lít).

- 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

it is the most commonly accepted one