Introduction to ionic equilibria in solution - class-XII

Boric acid is very weak acid since it dose not give $H^+$ , instead it takes $OH^-$ from $H _2O$ and become $B{ \left( OH \right)  } _{ 4 }^{ - }$ and Proton is lost from $H _2O$ not from boric acid.

True Because of movement of free ions in ionic solution, they are good conductor of electricity.

Degree of ionization $(\alpha)$ depends on-

B is correct

The degree of dissociation alpha is calculated by (normal molar mass - observed molar mass) / (observed molar mass * (n-1)). For AgNO3, n=2. (170-92.64) / (92.64 * 1) = 77.36 / 92.64 = 0.835, which is 83.5%.

protolysis (proton-transfer) reaction that takes place with very weak protonic acids, including water.

Using Graham's Law of Effusion, the ratio of molar masses is the square of the ratio of rates. M_mix = M_O2 / (2.084)^2 = 32 / 4.34 = 7.37. Using the equilibrium table, the total moles at equilibrium relate to Kp.

Dissociation in chemistry and biochemistry is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into smaller particles such as atoms, ions or radicals, usually in a reversible manner. It may or may not form charged species as shown below. 

i). $NaCl \leftrightharpoons Na^++Cl^-$

ii). $N _2O _4 \leftrightharpoons 2NO _2$

When electric current is passed through an electrolyte in its molten or aqueous state, the electrolyte is dissociated into its constituent ions.
Molten $NaCl$ breaks down to form $Na^+$ and $Cl^-$ where Sodium transfers its valence electron to Chlorine. So Sodium gets one positive charge and Chlorine gets one negative charge.
Molten $CaCl _2$ breaks down to form $Ca^{2+}$ and two $Cl^-$ ion where Calcium transfers its two valence electron to Chlorine. Hence Calcium gets two positive charges and each Chlorine atom gets one negative charge.

 Acid Strength refers to the degree of dissociation ( or ionization) in an aqueous solution. The greater the number of ions dissociated, or the number of cations and anions released in solution, the stronger the acid. Thus,  hydrochloric acid  dissociates completely into $H^+$ and $Cl^-$ ions in solution, so it is very strong. Acetic acid $(CH _3COOH)$,  dissociates feebly and releases few ions in solution, so it is  a weak acid.
Acid Concentration represents the amount of acid dissolved in a solvent. It is  measured in molarity ( the number of moles of acid in 1 L of acid solution), parts per million or percentage. The concentration is a ratio of the solute to solvent content of a solution. Acidic solutions with low numbers of acidic molecules/ions in solution are called dilute solutions whereas those with high numbers of acidic molecules/ions are called concentrated solutions.

Dissociation generally refers to breaking a compound into smaller pieces, usually reversibly. You can have dissociation without the formation of charged species.

When electric current is passed through an electrolyte in its molten or aqueous state, the electrolyte breaks up into its constituent ions.
When aqueous $KCl$ undergoes electrolysis, the ions $K^+$ and $Cl^-$ are formed where potassium transfers its one valence electron to Chlorine. So potassium becomes positively charged and chlorine becomes negatively charged.
When aqueous $MgCl _2$ undergoes electrolysis, the ions $Mg^{2+}$ and two $Cl^-$ ions are formed where magnesium transfers its two valence electron to chlorine. Thus magnesium gets two positive charges and each chlorine gets one negative charge.

The degree of ionization depends on nature of electrolyte, dilution of electrolyte, and temperature but does not depend on the volume of electrolyte.

Dissociation is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into smaller particles such as atoms, ions or radicals, usually in a reversible manner.

Hence, $ NaCl(aq.)\quad \rightleftarrows \quad { Na }^{ + }(aq.)\quad +\quad { Cl }^{ - }(aq.) $  is a dissociation reaction.

A net ionic equation is an equation that includes only the substances that are actually participating in the reaction.

Dissociation is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into smaller particles such as atoms, ions or radicals, usually in a reversible manner.

$ { Cl } _{ 2 }\rightarrow 2{ Cl }^{ \bullet  } $ - Radical formation is there.

$ KCl\rightarrow { K }^{ + }+{ Cl }^{ - } $ - Ion formation is there.

As the dissociation constant increases (A<B<C<D), dissociation of acid increases (A<B<C<D) and hence $[H^+]$ increases  (A<B<C<D) and hence pH value  decreases  (A>B>C>D). 

$HA + H _2O\rightleftharpoons A^+ + H _3O^+$
$K _a=\dfrac{[A^-].[H _3O^+]}{[HA]}=10^{-6}$
As the given reaction is the reverse of above reaction $K$ will the reciprocal of the above reaction.
Therefore, $K=10^6$

$Ka$ represents the ionisation constant of an acid. It is a measure of the strength of the acid, provided the temperature remains constant.

In dissociation separation of ions take place which are already present as ions in the solid state. For example in the crystal structure of $NaCl$, $NaCl$ is present as $Na$ and $Cl$.

$K _4Fe(CN) _6\longrightarrow 4K^++[Fe(CN) _6]^{-4}$

$\frac{h}{1-h}=\sqrt{KH}=\sqrt{\frac{kw}{K _{a}k _{b}}}=\sqrt{\frac{10^{-24}}{(3 \times 10^{-7})^{2}}}=\frac{1}{3}\Rightarrow h=0.25$

When more amount of solvent is added to the solution, it helps in dissociating the molecules into ions of a weak electrolyte. Thus, degree of dissociation of weak electrolyte increases upon dilution.

FInal concentration of $H _3O^+,[H _3O^+]$=$\cfrac {V _1S _1+V _2S _2}{V _1+V _2}$

For acetic acid/acetate buffer at pH 5.0, using Henderson-Hasselbalch: pH = pKa + log([base]/[acid]). pKa of acetic acid = 4.76. So 5.0 = 4.76 + log([base]/[acid]), giving log([base]/[acid]) = 0.24, so [base]/[acid] = 1.74. With total [base] + [acid] = 0.10 M: let [acid] = x, then [base] = 1.74x, so x + 1.74x = 0.10, x = 0.0365 M (acid) and [base] = 0.0635 M. Option B (0.06) matches the base concentration.

For an MX2 electrolyte, Ksp = [M^2+][X^-]^2 = (s)(2s)^2 = 4s^3. Given s = 0.5 * 10^-4, Ksp = 4 * (0.5 * 10^-4)^3 = 4 * 0.125 * 10^-12 = 0.5 * 10^-12 = 5 * 10^-13.

Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions. It does not split like in dissociation reaction.

Therefore, $ { H } _{ 2 }O\rightarrow \quad { H }^{ + }+{ { OH }^{ - } } $ is an ionization reaction. 

Degree of ionisation changes according to the temperature, concentration and the type of electrolyte like strong electrolyte or weak electrolyte, it does not varies with current.