Class 12th

Phenolphtalein is a pH dependant indicator. It is a weak acid which is colourless in acidic medium but gives pink colour in basic medium. The pink colour is due to its conjugate form. Phenolphthalein dissociates in basic medium. Therefore, assertion is true but reason is false.

$\underset{\left(Colourless\right)}{HPh\left(aq.\right)}?H^{+}+\underset{\left(Pink\right)}{P{h}^{-}}$

              44.4 litres of He $\frac{44.8}{22.4}moles$

            $\eta =2$    moles of He

              Q =   $\eta C_v\Delta T$ (for fixed capacity (v = constant)

              =   $2*\frac{R}{\gamma -1}\Delta T$

              =   $\frac{2*R}{\frac{5}{3}-1}*20$

= $=2*\frac{3R}{2}*20$

 Q = 60R = 60 * 8.3

  Q = 498 J

Urea acts as negative catalyst for decomposition of H₂O₂.

Liquation process is used for purification of that metal, whose melting point is lesser then that of impurities.

Ionic radius of Cl^- = 167 pm

Covalne radius of Cl = 99 pm

L₀ = RMV_cm + I_cm   $\omega$

 = RM   $\left(R\omega \right)+\frac{2}{3}M{R}^2\omega$

 L₀ =   $\frac{5}{3}M{R}^2\omega$

    $\frac{5}{3}*1R^2\omega =\frac{5}{3}{R}^2\omega =\frac{a}{3}{R}^2\omega$ =  

   a = 5

 $2S{O}_2\left(g\right)+O_2\left(g\right)\underset{}{\overset{V_2{O}_5}{\to }}2S{O}_3\left(g\right)contactprocess$

$4N{H}_3\left(g\right)+5O_2\left(g\right)\underset{}{\overset{A\left(s\right)-Rh\left(s\right)}{\to }}4NO\left(g\right)+6H_{2}O\left(g\right)$ ostwald's process

$N_2\left(g\right)+3H_2\left(g\right)\underset{}{\overset{Fe\left(s\right)}{\to }}2N{H}_3\left(g\right)Haber\text{'}sprocess$

Vegetable oil (l) + H₂ $\underset{}{\overset{Ni\left(s\right)}{\to }}$ vegetable ghee; Hydrogenation

Other name of animal starch is glycogen.

BrF₅       -             Square pyramid

[CrF₆]^3- -             Octahedral

O₃          -             Bent

PCl₅       -             Trigonal Bipyramid

Vulcanization of rubber is carried out by heating a mixture of isoprene and sulphur.