If $f(2)=4$ and $f^{\prime}(2)=1$,then $\lim _{x \rightarrow 2} \frac{x f(2)-2 f(x)}{x-2}$ is equal to

How many $mL$ of perhydrol is required to produce sufficient oxygen which can be used to completely convert $2 \ L$ of $SO_2$ gas to $SO_3$ gas (in $mL$)?

$A$ train whistling at a constant frequency is moving towards a station at a constant speed $V_s$. The train goes past a stationary observer on the station. The frequency $n'$ of the sound as heard by the observer is plotted as a function of time $t$. Identify the expected curve.

The disease known as fluorosis is caused by the reaction of fluorine with which of the following?

The value of $\lambda$ such that $\lambda x^2-10 x y+12 y^2+5 x-16 y-3=0$ represents a pair of straight lines is:

Which of the following reagents is used in the Gatterman-Koch formylation of arene?