Jelly is a colloidal solution of

In the process of transcription,the sigma factor is important for:

$AgNO_3 \xrightarrow{\Delta} (W) + (X) + O_2$
$(X) + H_2O \to HNO_2 + HNO_3$
$(W) + HNO_3 \to (Y) + NO + H_2O$
$(Y) + Na_2S_2O_3 (\text{excess}) \to (Z) + NaNO_3$
Identify $(W)$ to $(Z)$.

$A$ source of sound is travelling with a velocity of $40\, km/h$ towards an observer and emits sound of frequency $2000\, Hz$. If the velocity of sound is $1220\, km/h$,what is the apparent frequency heard by the observer in $Hz$?

In $\Delta ABC$,the expression $a(\cos^2 B + \cos^2 C) + \cos A(c \cos C + b \cos B)$ is equal to:

The $pK_a$ of a weak acid is $4.8$. What should be the ratio of $[Acid]/[Salt]$ of a buffer if $pH = 5.8$ is required?