Question

how to find the state of matter of a substance if its melting point, boiling point and room temperature is given

Answer 1

State of matter of a substance is decided by the melting point, boiling point and Room Temperature. Let us consider a substance having Melting point say "M", boiling point say "B" and Room temperature say "RT".
If M<RT and B<RT means the substance will melt as well as boil below RT. It means the substance will be in gaseous state at RT.
If M<RT and B>RT means the substance will melt at RT but do not boil at RT. It means the substance will be in liquid state at RT.
If M>RT and B>RT means the substance will not boil and also do not melt at RT. It means the substance will be in solid state at RT.