Basic Buffer Action

Q. The molar solubility of $Zn{\left(OH\right)}_2$ in 0.1 M NaOH solution is $x\times {10}^{-18}M$. The value of x is .......(Nearest integer)
(Given: The solubility product of $Zn\left(OH\right){}_2\text{is}2\times {10}^{-20}$)

Q. Which will make basic buffer ?

1. $100mLof0.1MHCl+200mLof0.1MN{H}_{4}OH$
2. $100mLof0.1MC{H}_{3}COOH+100mLof0.1MNaOH$
3. $50mLof0.1MNaOH+25mLof0.1MC{H}_{3}COOH$
4. $100mLof0.1MHCl+100mLof0.1MNaOH$

Q. The pH of a solution obtained by mixing 100ml of 0.2 M CH3COOH with 100 ml of 0.2 M NaOH will be

Q. Solution of 0.1 N $N{H}_{4}OH$ and 0.1 N $N{H}_{4}Cl$ has pH 9.25. $p{K}_b$ of $N{H}_{4}OH$ is :

1. 9.25
2. 4.75
3. 3.75
4. 8.25

Q. The precipitate of $Ca{F}_2$ with $K_{sp}$ equal to $1.7\times {10}^{-10}$ is obtained when equal volumes of the following are mixed?

1. ${10}^{-4}MC{a}^{2+}+{10}^{-4}M{F}^{-}$
2. ${10}^{-2}MC{a}^{2+}+{10}^{-3}M{F}^{-}$
3. ${10}^{-5}MC{a}^{2+}+{10}^{-3}M{F}^{-}$
4. ${10}^{-3}MC{a}^{2+}+{10}^{-5}M{F}^{-}$

Q. $C{H}_{3}N{H}_2$ (0.1 mole $K_b$ = 5 $\times {10}^{-4})$ is added to 0.08 mole of HCl and the solution is diluted to one litre, resulting hydrogen ion concentration is

1. $1.6\times {10}^{-11}$
2. $8\times {10}^{-11}$
3. $5\times {10}^{-5}$
4. $8\times {10}^{-2}$

Q.

$0.1\mathrm{N}\mathrm{NaOH}$ is required to neutralize $10\mathrm{mL}$, $0.1\mathrm{N}$ of Phosphonic Acid. Calculate its volume (in mL).

Q.

Hydrogen chloride ( $HCl$) gas is very soluble in water and is dissolved in water to get Hydrochloric acid by using an anti suction device with the mouth of the funnel just below the surface of the water. Explain how this device prevents the suction of water into the flask in which Hydrogen chloride is produced.

Q. Find out the solubility of $AgCl$ in $0.1MHCl$. Given that the ionic product of $AgCl$ is $1.8\times {10}^{-10}$.

1. $1.8\times {10}^{-10}M$
2. $1.8\times {10}^{-9}M$
3. $1.34\times {10}^{-5}M$
4. $1.25\times {10}^{-8}M$

Q.

pH of oxygenated blood is ___________.

Q. At 100C the kw of water is 55times its value at 25C what will be the ph of neutral solution

Q.

Consider the below-given reaction. The percentage yield of an amide product is ______. (Round off to the Nearest Integer).

[Given: Atomic mass: $\mathrm{C}$$=12.0u$, $\mathrm{H}$$=1.0u$, $\mathrm{N}$$=14.0u$, $\mathrm{O}$$=16.0u$, $\mathrm{Cl}$$=35.5u$]

Q. Basic buffer is made up of ?

1. Weak base and Weak acid
2. Weak base and its conjugate salt with strong acid
3. Weak base and strong acid
4. Strong base and its conjugate salt with weak acid

Q.

Which of the following mixtures will have the lowest pH at 298 K ?

1. $10\mathrm{ml}0.05\mathrm{N}{\mathrm{CH}}_3\mathrm{COOH}+5\mathrm{ml}0.1\mathrm{N}{\mathrm{NH}}_4\mathrm{OH}$

2. $5\mathrm{ml}0.1\mathrm{N}{\mathrm{NH}}_4\mathrm{Cl}+5\mathrm{ml}0.2\mathrm{N}{\mathrm{NH}}_4\mathrm{OH}$

3. $5\mathrm{ml}0.01\mathrm{N}{\mathrm{CH}}_3\mathrm{COOH}+10\mathrm{ml}0.05\mathrm{N}{\mathrm{CH}}_3\mathrm{COONa}$

4. $5\mathrm{ml}0.1\mathrm{N}\mathrm{CH}3\mathrm{COOH}+5\mathrm{ml}0.2\mathrm{N}\mathrm{NH}4\mathrm{OH}$

Q. calculate the normality of250 ml aqueous solution ofH2SO4 having pH=0.0

Q. 1000 ml of tap water containing $Ca(HC{O}_3{)}_2$ was titrated with $\frac{N}{50}$ HCl with methyl orange as indicator. If 300 ml of HCl were required, calculate temporary hardness as parts of $CaC{O}_{3}per{10}^6$ parts of water

1. 150 ppm
2. 300 ppm
3. 450 ppm
4. 600 ppm

Q. Freshly precipitated aluminium and magnesium hydroxides are stirred vigorously in a buffer solution containing $0.05{\text{mol L}}^{-1}$ of $N{H}_{4}OH$ and $0.25{\text{mol L}}^{-1}$ of $N{H}_{4}Cl$. Calculate the concentration of magnesium ions in solution.
$K_{sp}Al(OH{)}_3=6\times {10}^{-32}$
$K_{b}N{H}_{4}OH=1.8\times {10}^{-5}$
$K_{sp}Mg(OH{)}_2=6\times {10}^{-10}$

Q. Buffer capacity is maximum when:

1. One mole of ${NH}_{4}Cl$ is added to two moles of ${NH}_{4}OH$
2. One mole of ${NH}_{4}Cl$ is added to one moles of ${NH}_{4}OH$
3. One mole of ${NH}_{4}Cl$ is added to one mole of ${NH}_{4}OH$
4. One mole of $NaCl$ is added to one moles of ${NH}_{4}OH$

Q.

$100\mathrm{ml}$of tap water containing $\mathrm{Ca}{\left({\mathrm{HCO}}_3\right)}_2$ was titrated with$\frac{N}{50}$ $\mathrm{HCl}$with methyl orange as indicator. If $30\mathrm{ml}$ of $\mathrm{HCl}$ were required, what is the degree of temporary hardness as ppm?

Q. How do you calculate the $pH$ of a buffered solution?

1. By determining $Ka$, then using $Ka$ to determine the pH.
2. By using the equation $Ka=\left[H3O^{+}\right]\left[X^{-}\right]/\left[HX\right]$
3. By determining the $O{H}^{-}$ concentration.
4. By using the equation $Ka=\left[H3O^{+}\right]\left[X^{-}\right]$
5. By using the equation $Ka=\left[H{X}^{+}\right]\left[X^{-}\right]/\left[H3O^{+}\right]$

Q. A $1L$ aqueous solution is made by mixing $N{H}_{4}OH$ and $HCl$ solution at ${25}^{\circ }C$.
This can act as a basic buffer when :

1. Molar concentration of weak base is more than the molar concentration of strong acid i.e $\left[N{H}_{4}OH\right]>\left[HCl\right]$
2. Molar concentration of weak base is less than the molar concentration of strong acid i.e $\left[N{H}_{4}OH\right]<\left[HCl\right]$
3. Molar concentration of weak base is equal to the molar concentration of strong acid i.e $\left[N{H}_{4}OH\right]=\left[HCl\right]$
4. A basic buffer is always formed by $N{H}_{4}OH$ and $HCl$

Q. H2S(0.1M)+HCl(0.3M). Ka=1.2*10^-20 , find ph

Q. $pH$ of a salt of strong base with weak acid

1. $pH=\frac{1}{2}p{K}_w-\frac{1}{2}p{K}_a-\frac{1}{2}\log C$
2. $pH=\frac{1}{2}p{K}_w+\frac{1}{2}p{K}_a-\frac{1}{2}\log C$
3. $pH=\frac{1}{2}p{K}_w+\frac{1}{2}p{K}_a+\frac{1}{2}\log C$
4. $Noneofthese$

Q. $N{H}_{4}OH$ is titrated with $HCl$ solution. Find the value of $\log \left(\frac{\left[N{H}_4^{+}\right]}{\left[N{H}_{4}OH\right]}\right)$ when the volume of $HCl$ added is half of that of equivalence point.

1. \N
2. 0.5
3. 0.75
4. 1

Q.

What is the correct representation of Handerson Haselbalchs equation for acidic buffer?

Q. $pH$ of resultant solution formed by mixing equal volumes of two solutions having $pH=5.8$ and $pH=12.8$ is

1. $12.5$
2. $5.5$
3. $6.1$
4. $13.1$

Q. $p{K}_b$ for $N{H}_{4}OH$ at certain temperature is 4.74 The pH of basic buffer containing equimolar concentration of $N{H}_{4}OH$ and $N{H}_{C}I$ will be:

Q. A solution is $0.1M$ in each $KCl,KBr$ and $K_{2}Cr{O}_4$. To this solution solid $AgN{O}_3$ is gradually added. Assume no change in the volume of the solution.
Given: $K_{sp}\left(AgCl\right)=1.7\times {10}^{-10}$
$K_{sp}\left(AgBr\right)=5\times {10}^{-13}$
and $K_{sp}\left(A{g}_{2}Cr{O}_4\right)=1.9\times {10}^{-12}$

The concentration of first ion when the second ion starts precipitating is:

1. $0.1M$
2. $0.03M$
3. $0.003M$
4. $0.0003M$

Q. Find the $pH$ of $1L$ of a buffer solution containing $0.01MN{H}_{4}Cl$ and $0.05MN{H}_{4}OH$ at ${25}^{\circ }C$
The base dissociation constant for $N{H}_{4}OH$ is $1.8\times {10}^{-5}$
Take $log\left(1.8\right)=0.26$

1. 11.56
2. 12.56
3. 9.96
4. 10.36

Q. 100ml of 0.1 M NaOH is added to 100 ml of a 0.2 M $C{H}_{3}COOH$ solution. The pH of resulting solution will be (pka=4.74) :