If 0.2 g of nitrobenzene are added to 10.9 g of naphthalene, calculate the molality of the solution. (given: molar mass of nitrobenzene = 123.06 g/mole) report answers to one decimal place

Molality is defined as 1 mole of a solute in 1 kg of solvent.  

Molality=

Number of moles of solute, n=  

Given mass of the nitrobenzene=0.2 g

Molar mass of the substance= 123.06 g mol⁻¹

Number of moles of nitrobenzene,  

Number of moles of nitrobenzene, n= 0.0016  mol

Mass of 10.9 g of naphthalene in kg=0.0109  

Molality= 0.146 m

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.