Eli states that sodium phosphate is a mixture because it is composed of both sodium ions and phosphate ions. Which is the best analysis of Eli’s statement?

It is correct because each ion is a pure substance, so sodium phosphate is made up of two pure substances.
It is correct because the composition of sodium phosphate changes depending on the sample.
It is incorrect because sodium phosphate is a compound that has a single composition.
It is incorrect because the two types of ions in sodium phosphate cannot be seen.

It is incorrect because sodium phosphate is a compound that has a single composition.

Explanation:

Sodium phosphate is a compound and not a mixture. It is made up of sodium and phosphate ions and they exists as just a single compound and not different entities.

The parts of a mixture exists separately and they retain their identities.

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.