A scientist produces zinc iodine. This is the method used: 1.weight 0.500 g of iodine 2.dissolve the iodine in ethanol
3.add the excess of zinc
4. stir the mixture until there's no further change
5. filter the excess zinc
6. evaporate off the ethanol
explain why the scientist adds excess zinc rather then excess iodine

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock

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.