Ncert Solutions Chemistry Class 11th

For combustion of Mg:

Mg (s) + $\frac{1}{2}{O}_2\left(g\right)\to MgO\left(s\right)$

Here,   $\Delta ng=-\frac{1}{2}$

Now using

$\Delta H=\Delta U+\Delta ngRT$

-601.7 =   $\Delta U+\left(-\frac{1}{2}\right)*8.3*10^{-3}*300$

$\Delta U=-600.45kJ$

So; magnitude of   $\Delta U$ is 600 kJ (the nearest integer).

In extraction of copper from copper pyrite (CuFeS₂).

FeS converted to FeO as;

$\underset{Gangue}{2FeS}+3O_2\stackrel{\Delta }{\to }\underset{Gangue}{2FeO}+2S{O}_2$          

Then FeO is removed as slag by given reaction

FeO + SiO₂ ®   $\underset{Slag}{FeSi{O}_3}$

Metallic suphides i.e CdS are negatively charged colloidal solution.

Starch colloid is macro molecular colloidal solution.

Fe₂O₃. xH₂O sol is positively charged colloidal solution.

Cheese is an example of gel.

$?T_b=i{K}_{b}m$

$?T_f=i{K}_{f}m$

$?\frac{4}{4}=\frac{K_b*1.5}{K_f*4.5}$

$\frac{K_b}{K_f}=3$

Moles of N₂O $\frac{2.2}{44}=\frac{1}{20}$

$\Delta H=n{C}_p\Delta T=\frac{1}{20}*100\left(-40\right)=-200J$

$\Delta U=q_p+w$

$w=-P_{ext}.\Delta V$

$w=-1\frac{\left(167.75-217.1\right)}{1000}*101.3J=+5J$

$\Delta U=-200+5=195J$

$BaC{l}_2+S{O}_3^{2-}\stackrel{}{\to }\underset{White}{BaS{O}_3}\downarrow \stackrel{dil.HCl}{\to }\underset{\begin{array}{l}burningsulphur\\ likesmell\end{array}}{S{O}_2\uparrow }$

Data is not sufficient but official answer is (D)

For 2S, number of radial moles = $n-\mathcal{l}-1=2-0-1=1$ $$ and ${}^{}$ ${\Psi }^2\left(r\right)$ will always be positive

$$ $\therefore option\left(B\right)iscorrect?$  it has one radial node and it is positive.

$\frac{0.02858*0.112}{0.5702}=0.0561$

Here, total meq of acetic acid = 50 * 0.1 = 5

And total meq of NaOH = 25 * 0.1 = 2.5

After neutralization process

Meq of left acetic acid = 2.5

And meq of formed CH₃COONa = 2.5

$pH=pKa+lo{g}_{10}\frac{\left[S\right]}{\left[A\right]}$

$pH=4.76+lo{g}_{10}\frac{2.5}{2.5}=4.76=476*10^{-2}$