Which of the following is incapable of showing the iodoform test?

How many primary alcohols (including stereoisomers) are possible with formula $C_5H_{12}O$?

Given below are two statements:
Statement $(I)$: The boiling points of alcohols and phenols increase with an increase in the number of $C$ atoms.
Statement $(II)$: The boiling points of alcohols and phenols are higher in comparison to other classes of compounds such as ethers and haloalkanes.
In the light of the above statements,choose the correct answer from the options given below:

$CH_3 CH_2 OH \underset{\text{step-}1}{\stackrel{Cl_2}{\longrightarrow}} CH_3 CHO$ $\underset{\text{step-}2}{\stackrel{3 Cl_2}{\longrightarrow}} Cl_3 CCHO$
In the above reactions,the role of $Cl_2$ in step-$1$ and step-$2$ respectively is:

Glycerol reacts with conc. $HNO_3$ and conc. $H_2SO_4$ to form

Which of the following compounds gives the most stable carbonium ion during dehydration?