% of Cu, Fe, Ag are 98.88, 0.831, 0.289 respectively.

Kohlrausch's law of independent migration of ions It states that limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation-sf the electrolyte. If  \(\Lambda ^{ 0 }_{ Na^{ + } }\)and  \(\Lambda ^{ 0 }_{ CI^{ - } }\)
are limiting molar; conductivity of the sodium and chloride ions, respectively, then the limiting molar conductivity for NaCI is
\(\Lambda ^{ 0 }_{ Na^{ + } }(NaCI)\)  \(\Lambda ^{ 0 }_{ Na }+\Lambda ^{ 0 }_{ ci }\)
Calculation of degree of dissociation of weak electrolyte such as acetic acid. 
Degree of dissociation \(\left( \alpha \right) \)
\(=\frac { \Lambda ^{ c }_{ m }(Molar \ conductivity \ at \ any \ conc) }{ \Lambda ^{ c }_{ m }(Limiting \ molar \ conductivity) } \)

K = 5.25 x 10^-5 S cm^-1, M = 2.5 x 10^-4 M.
\(\lambda_{\mathrm{HCOOH}}^{0}=\lambda_{\left(\mathrm{HCOO}^{-}\right)}^{0}+\lambda_{\mathrm{H}}^{0}+\) 
= 349.5 + 50.5 : 400 S cm² mol^-1.
\(\Lambda_{m}=\frac{1000 \kappa}{\mathrm{M}}=\frac{1000 \times 5.25 \times 10^{-5}}{2.5 \times 10^{-4}}\) 
= \(\frac{1000 \times 525}{10 \times 2.5 \times 100}\) 
\(\Rightarrow \quad \Lambda_{m}=\frac{525}{2.5}=\frac{5250}{25}=210 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1}\) 
\(\alpha=\frac{\Lambda_{\mathrm{m}}}{\Lambda_{\mathrm{m}}^{0}}=\frac{210}{400}=\frac{21}{40}=0.525\) 
\(\Rightarrow \ \alpha\) =  0.525 x 100% = 52.5%

Cr²⁺ has electronic configuration 3d⁴ Chromium also shows +3 and +6 oxidation states. Fe²⁺ has electronic configuration 3d⁶. Iron has oxidation states +2 and +3.

Nickel-cadmium cell:
t is another type of secondary cell which has longer life than lead storage cell but more expensive to manufacture. The overall reaction during discharge is 
\(Cd(s)+{ 2Ni(OH) }_{ 3 }(s)\rightarrow CdO(s)+{ 2Ni(OH) }_{ 2 }(s)+{ H }_{ 2 }O(l).\)
Merit:
It is easy to handle as it is less bulky than lead storage cell and has longer life than lead storage cell.
Demerit:
It is more expensive than lead storage cell.

d = 1.9 9 mL^-l, W_B= 99.0 g, M₈ = 98 9 mol^-1,
\(Volume={Mass\over Density}={100\over 1.9}cm3\)
\(Molanty(M) ={W_B\over M_B}\times{1000\over vol.\ of\ solution}\)
\(={99\over 98}\times{1000\over {100\over 1.9}}=19.19M\)

(i) It is because its conductance is intermediate between conductor and insulator.
(ii) In Schottky defect, both cations and anions are missing which lead to lowering in the density of a solid.
(iii) The glass is supercooled liquid, therefore, very old glass objects become slightly milky because of heating during the day and cooling at nights, i.e. annealing over a number of years, glass acquires some crystalline structure.

Since the lattice is ccp, the number of silver atoms per unit cell = z = 4
Molar mass of silver = 107.9 mol^-1 = 107.9 x 10^-3 kg mol^-1
Edge length of unit cell = a = 408.6 pm = 408.6×10^-12 m
\(\text { Density, } d=\frac{z \cdot \mathrm{M}}{\mathrm{a}^{3} \cdot \mathrm{N}_{\mathrm{A}}}\)
\(=\frac{4 \times\left(107.9 \times 10^{-3} \mathrm{~kg} \mathrm{~mol}^{-1}\right)}{\left(408.6 \times 10^{-12} \mathrm{~m}\right)^{3}\left(6.022 \times 10^{23} \mathrm{~mol}^{-1}\right)}=10.5 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}\)
= 10.5 g cm^-3

60 u