13.3 g of benzene (c6h6) is dissolved in 282 g of carbon tetrachloride. what is the molal concentration of benzene in this solution?

0.605 molal

Explanation:

molality is the amount of solute in a particular mass of solvent.

lets calculate the amount of benzene solute.

mass of benzene= 13.3g

molar mass of C6H6= 12*6 +1*6 =72+7=78g/mol

amount of benzene= mass/molar mass

                           =13.3/78

                          =0.1705mol

molality= amount of solute/mass of solvent in kg

mass of solvent=282g=0.282kg

molality = 0.1705/0.282

    =0.605 molal

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.