Answer the lab question “how can you use flame color to identify the metal ion in an unknown compound? ” by filling in the boxes below to create a hypothesis. ……… ……….

We have to know how flame colour can be used to identify the metal ion in an unknown compound.

If golden yellow coloured flame , then Na⁺ ion because electrons get excited on heating and again fall back to emit energy of definite wavelengths corresponding to particular colour in the visible region.

If violet coloured flame , then K⁺ because electrons get excited on heating and again fall back to emit energy of definite wavelengths corresponding to particular colour in the visible region.

If crimson red coloured flame , then Sr²⁺ because electrons get excited on heating and again fall back to emit energy of definite wavelengths corresponding to particular colour in the visible region.

If yellowish green coloured flame , then Ba²⁺ because electrons get excited on heating and again fall back to emit energy of definite wavelengths corresponding to particular colour in the visible region.

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.