Combustion equation for ethane is :

C₂H₆ (g) +$\frac{7}{2}$O₂ (g)$\to$2CO₂ (g) + 3H₂O (g)$∆$$\mathrm{H}°$= ?

$∆\mathrm{H}°$= {$\mathrm{\Sigma }∆{\mathrm{H}}_{\mathrm{f}}^{°}$products} - {$\mathrm{\Sigma }∆{\mathrm{H}}_{\mathrm{f}}^{°}$reactants}

= {2$∆{\mathrm{H}}_{\mathrm{f}}^{°}$(CO₂) + 3$∆$H_f (H₂O)} - {$∆{\mathrm{H}}_{\mathrm{f}}^{°}$(C₂H₆) + 7/2$∆{\mathrm{H}}_{\mathrm{f}}^{°}$(O₂)}

{2 X (- 94.1) + 3 X (- 68.3)} - {(-21.1) + 7/2(O)}

={- 1888.2 - 204.9} - {-21.1}

= - 393.1 + 21.1

= - 372 kcal

C₂➔ the molecular orbital configuration (12) is

➔ C₂ = [($\mathrm{\sigma }$1s)² ($\stackrel{*}{\mathrm{\sigma }}$1s)² ($\mathrm{\sigma }$2s)² ($\stackrel{*}{\mathrm{\sigma }}$2s)² ($\mathrm{\pi }$2p_y)² ($\mathrm{\pi }$2p_z)²]

C₂ molecule is diamagnetic as it does notcontain any unpaired electron

N₂➔the molecular orbital configuration (14) is

➔N₂ = [($\mathrm{\sigma }$1s)² ($\stackrel{*}{\mathrm{\sigma }}$1s)² ($\mathrm{\sigma }$2s)² ($\stackrel{*}{\mathrm{\sigma }}$2s)² ($\mathrm{\pi }$2p_y)² ($\mathrm{\pi }$2p_z)² ($\mathrm{\sigma }$2p_x)²]

N₂ molecule is diamagnetic because it does notcontain any unpaired electron .

N₂⁺➔the molecular orbital configuration (13) is

➔ N₂⁺ = [($\mathrm{\sigma }$1s)² ($\stackrel{*}{\mathrm{\sigma }}$1s)² ($\mathrm{\sigma }$2s)² ($\stackrel{*}{\mathrm{\sigma }}$2s)² ($\mathrm{\pi }$2p_y)² ($\mathrm{\pi }$2p_z)² ($\mathrm{\sigma }$2p_x)¹]

N₂⁺molecule is paramagnetic because it containone unpaired electron .

O₂^2-➔the molecular orbital configuration (18) is

➔O₂^2- = [($\mathrm{\sigma }$1s)² ($\stackrel{*}{\mathrm{\sigma }}$1s)² ($\mathrm{\sigma }$2s)² ($\stackrel{*}{\mathrm{\sigma }}$2s)² ($\mathrm{\sigma }$2p_x)² ($\mathrm{\pi }$2p_y)² ($\mathrm{\pi }$2p_z)² ($\stackrel{*}{\mathrm{\pi }}$2p_y)²($\stackrel{*}{\mathrm{\pi }}$2pz)2]

It does not contain any unpaired electron so , it isdiamagnetic .

$···\stackrel{{\mathrm{\delta }}^{+}}{\mathrm{H}}-\stackrel{{\mathrm{\delta }}^{-}}{\mathrm{F}}···\stackrel{{\mathrm{\delta }}^{+}}{\mathrm{H}}-\stackrel{{\mathrm{\delta }}^{-}}{\mathrm{F}}···$

Strength of H · · · · · F > H · · · · · O

NH₂COONH₄ (s)$\rightleftharpoons$2NH₃ (g) + CO₂ (g)

On applying the law of mass action to thisheterogeneous system

K_p =$\frac{{\mathrm{P}}_{{\mathrm{NH}}_3}^2\times {\mathrm{P}}_{{\mathrm{CO}}_2}}{{\mathrm{P}}_{{\mathrm{NH}}_2{\mathrm{COONH}}_4\left(\mathrm{s}\right)}}$

or K_p =${\mathrm{P}}_{{\mathrm{NH}}_3}^2$X${\mathrm{P}}_{{\mathrm{CO}}_2}$

= 3²X3

= 9 X 3 = 27

Non - directional orbital is : 3s because s - sub - shellhas only one orbital and it is spherical .Hence ,s - orbitals are non - directional .

In CO₂ ,the bond length (C-O) is 1.15$\stackrel{°}{\mathrm{A}}$,hybridization of C in CO₂ is sp .Thus it has alinear structure .

O=C=O$\leftrightarrow$O⁺=C-O^-$\leftrightarrow$O^--C$\mathrm{\equiv }$O⁺ .

Due to increase in the atomic size of zero groupelements from He to Xe , the polarizability oftheir atom by a polar solvent increases in thesame order .Thus Xe is most polarised .

When an alpha particle is ejected , results in

➔ decrease in atomic weight by four units

➔ decrease in atomic number of twoWhen a beta particle is ejected , results in

➔ no change in atomic weight

➔ increase in atomic number by one unitwhen an$\mathrm{\gamma }$ particle is ejected results in

➔ nochange

₇₂X¹⁸⁰$\stackrel{2\mathrm{\alpha }}{\to }$₆₈A¹⁷²$\stackrel{-1\mathrm{\beta }}{\to }$₆₉B¹⁷²$\stackrel{\mathrm{\gamma }}{\to }$₆₉X¹⁷²

When a radioactive nucleus are passed throughelectric or magnetic field , they are split intoradioactive rays .A radioactive substance firstemits$\mathrm{\alpha }$ and$\mathrm{\beta }$ radiations , then it becomesunstable and emit rays .

We know ,

V_rms =$\sqrt{\frac{3\mathrm{PV}}{\mathrm{M}}}$

=$\sqrt{\frac{3\mathrm{RT}}{\mathrm{M}}}$

Given V_rms = 30R^1/2

T = 273 + 27 = 300 K

30R^1/2 =$\sqrt{\frac{3\mathrm{RT}}{\mathrm{M}}}$

$\sqrt{{30}^2}\mathrm{R}$=$\sqrt{\frac{3\mathrm{RT}}{\mathrm{M}}}$

30 x 30 x R =$\frac{3\mathrm{x}\mathrm{R}\mathrm{x}300}{\mathrm{M}}$

M =$\frac{3\mathrm{x}\mathrm{R}\mathrm{x}300}{30\mathrm{x}30\mathrm{x}\mathrm{R}}$

= 1g = 0.001 kg