Explanation:
2,3-diethyl hexane
At first we select a long chain.
Then, we number that chain from that side where substituent position is closer.
Then, we write it's IUPAC name
Position of substituent + substituent name + chain name + suffix
Here,
2,3 + -diethyl + hex + -ane
= 2,3-diethyl hexane
The answer is 0.600 M; but I don't know how to get to that answer.
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
Answer:
n=N/NA
n= 3.754×10²³/6.02×10²³
n= 6.24 s
Explanation
since there is number of molecules, make use of Avogadro's constant to get number of moles.