Examples of hard water​

lake water, swamp water, like, any dirty and unpurified forms of water is hard water

Explanation:

Water is considered hard when it contains a large amount of the cations (positively-charged ions) Ca2+, Mg2+, and/or Fe3+. These ions are typically introduced into a water supply when the water drips through a mineral. Limestone is an example of a mineral that contains a source of calcium.

Explanation:

the electron configuration that you gave me has 16 electrons ergo it has 16 protons ergo it is the element sulfur.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.