In the following reaction sequence, the correct structure($s$) of $X$ is (are)

$\log _4 2 - \log _8 2 + \log _{16} 2 - \dots$ is equal to

$Assertion (A)$: van der Waals' forces are responsible for chemisorption. $Reason (R)$: High temperature is favourable for chemisorption. The correct answer is

A linear octasaccharide $($molar mass $=1024 g mol ^{-1} )$ on complete hydrolysis produces three monosaccharides: ribose, $2-$deoxyribose and glucose. The amount of $2-$deoxyribose formed is $58.26 \%( w / w )$ of the total amount of the monosaccharides produced in the hydrolyzed products. The number of ribose unit$(s)$ present in one molecule of octasaccharide is $.....$
Use : Molar mass $($in g $mol ^{-1} )$: ribose $=150,2-$deoxyribose $=134$, glucose $=180$; Atomic mass $($in amu$): H =1, O =16$

The potential difference between two parallel plates is $10^4 ~V$. If the plates are separated by $0.5 ~cm$,the force on an electron between the plates is

The number of subsets of $\{1, 2, 3, \ldots, 9\}$ containing at least one odd number is