Class 11th

Density of metal a very specific and depends upon many factors.

Li ® 0.53 gm/cm³

Na ® 0.97 gm/cm³

K ® 0.86 gm/cm³

Rb ®1.53 gm/cm³

Cs ® 1.90 gm/cm³

$$ $2Mn{O}_4^{-}+6H^{+}+5H_2{O}_2\to 2M{n}^{2+}+8H_{2}O+5O_2$
 

$\left[N{H}_{4}Cl\right]=\frac{2}{60}=\frac{1}{30}M$

$pH=7-\frac{1}{2}P{K}_b-\frac{1}{2}logC$

$=7-\frac{5}{2}-\frac{1}{2}log\left(\frac{1}{30}\right)=5.24$

Value of n & $\mathcal{l}$ can't be same

$S{O}_{2}C{l}_2+2H_{2}O\to H_{2}S{O}_4+2HCl$  

Let a moles of SO₂Cl₂ is taken

Then no. of moles of H₂SO₄ = a moles

No. of moles of HCl = 2a moles

No. of moles of NaOH required = 2a + 2a = 4a = 16

$\Rightarrow a=4moles$  

B₂H₆ has 4 2 c -2e bonds and 2 3c-2e bonds.

Bridging (B-H) bonds have more value of bond- length then terminal (B – H) bonds

Bridging bonds are in one plane, but terminal bonds are in perpendicular plane.

Due to presence of (3c-2e) bonds, it behaves as electrons deficient and prone to get attached by  lewis  base.

$3NaB{H}_4+4B{F}_3\underset{}{\overset{\Delta }{\to }}3NaB{F}_4+2B_2{H}_6$

$V_{rms}\alpha \sqrt[]{T}|T_i=127°C=400k.$

$V_{rm{s}^1}=2V_{rms},m=0.056kg=56g$

T_f = 4T_i = 4 * 400 = 1600 k

$Q=n{c}_v\Delta T=\left(\frac{m}{M}\right)C_v\Delta T$

= $\left(\frac{56}{28}\right)\frac{5}{2}R\Delta T$

= $2*\frac{5}{2}*2*1200$

Q = 12 * 10³ cal

= 12 k cal

Due to higher extent of polarization by Li⁺ and Mg²⁺, LiCl and Mgcl₂ have covalent character. Therefore they are soluble in ethanol.

 Due to very high value of lattice energy, LiF is having very less solubility in water.

Answer (3) 

Particles having phase difference of $?$ will move with same speed.

Sphalarite             ZnS

Calamine              ZnCO₃

Galena                  PbS

Siderite                FeCO₃