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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
What will be the `pH` of a solution formed by mixing `40 ml` of `0.10 M HCl` with `10 ml` of `0.45 M NaOH`?A. `12`B. `10`C. `8`D. `6` |
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Answer» Correct Answer - A `M.eq.` of `0.10 M HCl =(0.10)/(1000)xx40=0.004 M` `M.eq.` of `0.45 M NaOH=(0.45xx10)/(1000)=0.0045 M` Now left `[OH^(-)]=0.0045-0.004=5xx10^(-4)M` Total volume `= 50 ml` `[OH^(-)]=(5xx10^(-4))/(50)xx1000` , `[OH^(-)]=1xx10^(-2)` `pOH=2`, `pH=14-pOH=12` |
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| 102. |
Calculate the `pH` of a solution which contains `10 ml` of `1 M HCl` and `10 ml` of `2M NaOH`A. `11.7`B. `12.7`C. `13.7`D. `10.7` |
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Answer» Correct Answer - C `{:(,HCl,+,NaOH,to,NaCl,,H_(2)O),("Meq. before",10xx1,,10xx2,,,,),("Reaction",10,,20,,0,,0),("Meq.After",0,,10,,10,,10),("Reaction",,,,,,,):}` `[OH^(-)]` left from `NaOH=(10)/(20)=0.5 M` `pOH= -logOH^(-)= -log0.5` `pOH=0.3` `pH=13.7` |
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| 103. |
A buffer solution is prepared in which the concentration of `NH_(3)` is `0.30 M` and the concentration of `NH_(4)^(+)` is `0.20 M`. If the equilibrium constant, `K_(b)` for `NH_(3)` equals `1.8xx10^(-5)`, what is the `pH` of this solution? (`log 2.7=0.43`)A. `8.73`B. `9.08`C. `9.43`D. `11.72` |
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Answer» Correct Answer - C `pOH=pK_(b)+log``([Conjugate acid])/([base])` `= -log1.8xx10^(-5)+log``(0.2)/(0.3)` `= -log 1.8xx10^(-5)+log 0.66` `= 4.744-0.176=4.567` `:. pH=14-4.567=9.423` |
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| 104. |
For `NH_(3)`, `K_(b)=1.8xx10^(-5)`. `K_(a)` for `NH_(4)^(+)` would beA. `1.8xx10^(5)`B. `5.56xx10^(5)`C. `1.8xx10^(10)`D. `5.56xx10^(-10)` |
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Answer» Correct Answer - D `K_(a)xxK_(b)=K_(w)` `K_(a)=(K_(w))/(K_(b))= (10^(-14))/(1.8xx10^(-5))=5.56xx10^(-10)` |
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| 105. |
A reaction `CaF_(2)hArrCa^(2+)+2F^(-)` is at equilibrium. If the concentration of `Ca^(2+)` is increased four times, what will be the change in `F^(-)` concentration as compared to the initial concentration of `F^(-)`?A. `(1)/(4)` timesB. `(1)/(2)` timesC. `4` timesD. `2` times |
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Answer» Correct Answer - B The dissociation constant `K` of the reaction ` =([ca^(2+)][F^(-)]^(2))/([CaF_(2)])` When the concentration of `Ca^(2+)` increases and becomes four times, the conentration of `F^(-)` must decrease by the same value. This is necessary in order to maintain `K` as constant. Since the `F^(-)` concentration is raised to the power `2` in the expression, the concentration of fluoride ion must decrease by `1//2`. |
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| 106. |
What molar concentration of ammonia will provide a hydroxyl ion concentration of `1.5xx10^(-3)`? `(K_(b)=1.8xx10^(-5))`A. `0.125 M`B. `0.12 M`C. `0.13 M`D. `0.14 M` |
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Answer» Correct Answer - C The reaction is `NH_(3)+H_(2)OhArrNH_(4)^(+)+OH^(-)` `K_(b)=1.8xx10^(-5)=([NH_(4)^(+)][OH^(-)])/([NH_(3)])` `=((1.5xx10^(-3))(1.5xx10^(-3)))/([NH_(3)])=1.8xx10^(-5)` Equilibrium conc. Of ammonia `[NH_(3)]=0.125 M` And, total `[NH_(3)]=1.5xx10^(-3)+0.125=0.13 M` |
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| 107. |
Silver nitrate solution is gradually added to an aqueous solution containing `0.01 M` each of chloride, bormide and iodide ions. The correct sequence in which the halides will be precipitated is:A. Bromide, chloride iodideB. Iodide, chloride, bormideC. Iodide, bormide, chlorideD. Bromide chloride |
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Answer» Correct Answer - C The `K_(SP)` values are in the order: `AgClgtAgBrgtAgl` |
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| 108. |
The solubility product of a salt having general formula `MX_(2)` in water is `4xx10^(-12)`. The concentration of `M^(2+) ions` in the aqueous solution of the salt is:A. `2xx10^(-6) M`B. `1xx10^(-4) M`C. `1.6xx10^(-4) M`D. `4.0xx10^(-6) M` |
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Answer» Correct Answer - B `(MX_(2))hArrunderset(S)(M^(2+))+underset(2S)(2X^(-))` `K_(SP)MS_(2)=4S^(3)=4xx10^(-12)` `:. S=10^(-4)` `:. [M^(2+)]=10^(-4) M` |
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| 109. |
If the solubility product of `MOH` is `1xx10^(-10) mol^(2) dm^(-6)` then `pH` of its aqueous solution will beA. `12`B. `9`C. `6`D. `3` |
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Answer» Correct Answer - B `s=sqrt(K_(sp))=sqrt(1xx10^(-10))=1xx10^(-5) M` `[OH^(-)]=[MOH]=1xx10^(-5)` `[H_(3)O^(+)]=(1xx10^(-14))/(1xx10^(-5))=1xx10^(-9)` `pH= -log[H_(3)O^(+)]= -log 10^(-9) =9` |
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| 110. |
Orthoboric acid in aqueous medium isA. MonobasicB. DibasicC. TribasicD. All are correct |
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Answer» Correct Answer - A `H_(3)BO_(3)+H_(2)OhArr[B(OH)_(4)]^(-)+H^(+)` `H_(3)BO_(3)` is a weak monobasic acid if it does not act as a `H^(+)` donor but behaves as a lewis acid. |
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| 111. |
The solubility of `BaSO_(4)` in water is `2.33xx10^(-3) g//litre`. Its solubility product will be (molecular weight of `BaSO_(4)=233`)A. `1xx10^(-5)`B. `1xx10^(-10)`C. `1xx10^(-15)`D. `1xx10^(-20)` |
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Answer» Correct Answer - B The solubility of `BaSO_(4)` in `g//litre` is given `2.33xx10` `:.` In mole//litre `n=(W)/(m.wt.)=(2.33xx10^(-3))/(233)` `=1xx10^(-5)` Because `BaSO_(4)` is a compound `K_(sp)=S^(2)=[1xx10^(-5)]^(2)=1xx10^(-10)` |
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| 112. |
In which case `pH` will not change on dilutionA. `0.01 M CH_(3)COONa+0.01 M CH_(3)COOH` bufferB. `0.01 M CH_(3)COONH_(4)`C. `0.01 M NaH_(2)PO_(4)`D. in all cases |
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Answer» Correct Answer - D Mixture of sodium acetate and acetic acid is a buffer of `pH` value equal to `pK_(a)` so its buffer capacity is very high and hence its `pH` will not change signficantly while `CH_(3)COONH_(4)` is a salt of weak acid `CH_(3)COOH` and weak base `NH_(4)OH` whose magnitude of `K_(a)` and `K_(b)` are equal. So its `pH` does not depend upon concentration. Furthermore, `NaH_(2)PO_(4)` is , in fact, a single solute buffer |
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| 113. |
The precipitation occurs if ionic concentration isA. less than solubility productB. more than solubility productC. equal to solubility productD. None of these |
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Answer» Correct Answer - B Precipitation occurs when ionic product `gt` solubility. |
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| 114. |
Assertion : In a pair of two electrolytes one having higher value of `K_(SP)` is more soluble in water than the other having lower value of `K_(sp)`. Reason : Solubility of electrolyte depends upon `K_(sp)` as well as on the nature of electrolyte.A. If both assertion and reason are true and the reason is the correct explantion of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - D `K_(sp)=p^(p)xxa^(q)xxs^(p+q)` for `A_(p) B_(q)` Solubility depends on stoichiometry of salt. |
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| 115. |
Assertion : Degree of hydrolysis and `pH` of a salt, e.g. `NH_(4)CN` is independent of concentration of `NH_(4)CN` Reason : The solution of `NH_(4)CN` in water has `pH` slightly greater than `7`.A. If both assertion and reason are true and the reason is the correct explantion of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - B `NH_(4)OH` is relatively stronger than `HCN`. |
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| 116. |
Which of the following will not be hydrolysed?A. Potassium nitrateB. Potassium cyanideC. Potassium succinateD. Potassium carbonate |
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Answer» Correct Answer - A Because it is a salt of strong acid and strong base. |
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| 117. |
A weak base, `B`, has basicity constant `K_(b)=2xx10^(-5)`. The `pH` of any solution in which `[B]=[BH^(+)]` isA. `4.7`B. `7.0`C. `9.3`D. `9.7` |
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Answer» Correct Answer - C `B+H_(2)OhArrBH^(+)+OH^(-)` `K_(b)=([BH^(+)][OH^(-)])/([B])` or `K_(b)=[OH^(-)]` `POH=5-log2` `:. pH=14-pOH=9+log2=9.3` |
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| 118. |
The solubility of `CuBr` is `2xx10^(-4)` at `25^(@)C`. The `K_(sp)` value for `CuBr` isA. `4xx10^(-8) mol^(2) l^(-2)`B. `4xx10^(-11) mol^(2) L^(-1)`C. `4xx10^(-4) mol^(2) l^(-2)`D. `4xx10^(-15) mol^(2) l^(-2)` |
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Answer» Correct Answer - A `underset(K_(sp))(CuBr)hArrunderset((s))(Cu^(+))+ underset((S))(Br^(-))` `K_(sp)=S^(2)=(2xx10^(-4))^(2)=4xx10^(-8)(mol^(2))/(l^(2))` |
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| 119. |
In a solution total concentration of `M^(3+)` is `2xx10^(-3) (M)` and total concentration of `SCN^(-)` is `1.51xx10^(-3) (M)` and free `SCN^(-)` concentration `= 1xx10^(-5) (M)` What is the dissociation constant of the complex `M(SCN)^(2+)`?A. `2xx10^(5)`B. `2xx10^(-5)`C. `3.33xx10^(5)`D. `3.33xx10^(-6)` |
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Answer» Correct Answer - D `underset(50xx10^(-5))(M^(3+))+underset(10-5)(SCN^(-))overset(K_(form))underset(larr)(rarr)underset(150xx10^(-5))(M(SCN)^(2+))` `K_(form)=(150xx10^(-5))/(50xx10^(-5)xx10^(-5))=3xx105` `K_(disso)=(1)/(K_(form))=(1)/(3)xx10^(-5)` `=(10)/(3)xx10^(-6)=3.33xx10^(-5)` |
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| 120. |
The `pH` of `0.5 M` aqueous solution of `HF` `(K_(a)=2xx10^(-4))` isA. `2`B. `4`C. `6`D. `10` |
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Answer» Correct Answer - A `[H^(+)]=sqrt(CK_(a)) =sqrt(0.5xx2xx10^(-4))=10^(-2) M` `pH= -log 10 [H^(+)]= -log 10^(-2)=2` |
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| 121. |
When `0.1 m "mole"` of solid `NaOH` is added in `1 L` of `0.1 M NH_(3) (aq)` then which statement is going to be wrong? `(K_(b)=2xx10^(-5), log 2=0.3)`A. degree of dissociation of `NH_(3)` approaches to zero.B. change in `pH` would be `1.85`C. concentration of `[Na^(+)]=0.1 M, [NH_(3)]=0.1 M`, `[OH^(-)]=0.2 M`D. on addition of `OH^(-)`,`K_(b)` of `NH_(3)` does not changes |
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Answer» Correct Answer - C Initial `pOH=(1)/(2)(pK_(b)-log C)` `= (1)/(2)(4.7-log 0.1)=2.85` Final `pOH=1` Change in `pOH=`Change in `pH=1.85` |
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| 122. |
Assertion : The `pH` of human blood at body temperature is found to be `6.9`. Reason : Blood is alkaline in nature.A. If both assertion and reason are true and the reason is the correct explantion of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - D Blood is alkaline and at body temperature `(98^(@)F)` scale of `pH` lies between `0` and `13.6`. |
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| 123. |
An aqueous solution of sodium carbonate is alkaline because sodium carbonate is a salt ofA. Weak acid and weak baseB. Strong acid and weak baseC. Weak acid and strong baseD. Strong acid and strong base |
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Answer» Correct Answer - C `Na_(2)CO_(3)+2H_(2)OhArr2NaOH+H_(2)CO_(3)`. It is a strong base and weak acid so it is a basic. |
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| 124. |
An aqueous solution of sodium carbonate has a `pH` greater than `7` becauseA. It contains more carbonate ions than `H_(2)O` moleculesB. It cantains more hydroxide ions that carbonate ionsC. `Na^(+)` ions react with waterD. Carbonate ions react with `H_(2)O` |
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Answer» Correct Answer - B `pHgt7 =` Basic It means it contains more hydroxide ions than carbonate ions. |
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| 125. |
In the following reaction `HC_(2)O_(4)^(-)(aq)+PO_(4)^(3-)(aq)hArrHPO_(4)^(-2)(aq)+C_(2)O_(4)^(2-)(aq)`, which are the two Bronsted bases?A. `HC_(2)O_(4)^(-)` and `PO_(4)^(3-)`B. `HPO_(4)^(2-)` and `C_(2)O_(4)^(2-)`C. `HC_(2)O_(4)^(-)` and `HPO_(4)^(2-)`D. `PO_(4)^(3-)` and `C_(2)O_(4)^(2-)` |
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Answer» Correct Answer - D `underset(Acid1)(HC_(2)O_(4)^(-)(aq))+underset(base2)(PO_(4)^(3-)(aq))hArrunderset(base 1-)(HPO_(4)^(2-))(aq)+underset(acid 2)(C_(2)O_(4)^(2-))(aq)` |
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| 126. |
A solution of `HCl` contains `0.1920 g` of an acid in `0.5 litre` of a solution. The degree of dissociation is `95%`. The `pH` of the solution isA. `4.0`B. `2.0`C. `2.192`D. `1.92` |
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Answer» Correct Answer - B Concentration `C` of `HCl` solution `=(0.1920)/(36.5xx0.5)=0.010 M` The degree of dissociation is `95%`, i.e., `= 0.95` Therefore, `[H^(+)]=0.010xx0.95=0.0095` `pH =-log[H^(+)]= -log(0.0095)` `= -[bar3.(9777)]=-(-2.02)=2.0` |
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| 127. |
Hydrolysis constant for a salt of weak acid and weak base would beA. `K_(h)=(K_(w))/(K_(a))`B. `K_(h)=(K_(w))/(K_(b))`C. `K_(h)=(K_(w))/(K_(a)K_(b))`D. None of these |
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Answer» Correct Answer - C `K_(h)=(K_(w))/(K_(a)xxK_(b))` |
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| 128. |
In hydrolysis of a salt of weak acid and strong base, `A^(-)+H_(2)OhArrHA+OH^(-)`, the hydrolysis constant `(K_(h))` is equal toA. `(K_(w))/(K_(a))`B. `(K_(w))/(K_(b))`C. `sqrt((K_(a))/(C ))`D. `(K_(w))/(K_(a)xxK_(b))` |
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Answer» Correct Answer - A Hydrolysis constant, `h=(K_(w))/(K_(a))` |
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| 129. |
In which of the following salt hydrolysis takes placeA. `KCl`B. `NaNO_(3)`C. `CH_(3)COOK`D. `K_(2)SO_(4)` |
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Answer» Correct Answer - C Because it is a strong base. |
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| 130. |
Which of salt will give basic solution on hydrolysis?A. `KCN`B. `KCl`C. `NH_(4)Cl`D. `CH_(3)COONH_(4)` |
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Answer» Correct Answer - A `KCN` is salt of strong base and weak acid. |
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| 131. |
Which is a basic saltA. `PbS`B. `PbCO_(3)`C. `PbSO_(4)`D. `2PbCO_(3), Pb(OH)_(2)` |
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Answer» Correct Answer - D It is a salt of strong base and weak acid. |
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| 132. |
When `NH_(3)(0.1 M) 50 ml` mix with `HCl (0.1 M) 10 ml` then what is `pH` of resultant solution (`pK_(b)=4.75)`A. `9.25`B. `10`C. `9.85`D. `4.15` |
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Answer» Correct Answer - C `underset(rem.)underset()underset(Initial)(NH_(3))+underset(4mmol)underset(5mmol)underset(50xx0.1)(HCl) rarr underset(0)underset(1mmol)underset(10xx0.1)(NH_(4)Cl)` `pOH=pK_(b)+log``("salt")/(base)` `=4.75+log``(1)/(4)=4.15` `pH=14-pOH=14-4.15=9.85` |
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| 133. |
The `pH` of `0.02 M NH_(4)Cl (aq) (pK_(b)=4.73)` is equal toA. `3.78`B. `4.73`C. `5.48`D. `7.00` |
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Answer» Correct Answer - C `pH=(1)/(2)[pK_(w)-pK_(b)-log C]` `= (1)/(2)[14-4.73-log 0.02]` `= (1)/(2)[14-4.73+1.698]=5.48` |
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| 134. |
The `H^(+) ion` concentration is `1.0xx10^(-6)` mole/litre in solution. Its `pH` value will beA. `12`B. `6`C. `18`D. `24` |
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Answer» Correct Answer - B `[H^(+)]=100xx10^(-6) "mole"//litre` `pH= -log[1.00xx10^(-6)]`, `pH=6` |
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| 135. |
Find the `pH` of solution prepared by mixing `25 ml` of a `0.5 M` solution of `HCl, 10 ml` of a `0.5 M` solution of `NaOH` and `15 ml` of waterA. `0.8239`B. `1.0029`C. `1.0239`D. `1.8239` |
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Answer» Correct Answer - A We know that for `HCl` and `NaOH`, m.e.`=`milli`-`equivalent ` :. M.e.` of `HCl=0.5xx25=12.5` `m.e.` of `NaOH=0.5xx10=5.0` `m.e.` of `HCl` in the resultant mixture `=12.5-5.0=7.5` Total volume `=(25+10+15)ml=50ml` `:.` Normality of `HCl=(m.e)/(Vol(ml))=(7.50)/(50)` ` :.` Molarity `=(7.50)/(50)` `:. =[H^(+)]=[HCl]=(7.50)/(50)` `:. pH= -log(7.50)/(50)=0.8239` |
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| 136. |
The `pH` of `10^(-8)` molar aqueous solution of `HCl` isA. `-8`B. `8`C. `6gt7`(between `6` and `7`)D. `7gt8` (between `7` and `8`) |
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Answer» Correct Answer - C As the solution is acidic, `pHlt7`. This is because `[H^(+)]` from `H_(2)O[10^(-7)]` cannot be neglected in comparison to `10^(-8)` |
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| 137. |
Assertion: `0.1 M NaCN+0.05 M HCl` solution on mixing in equal volume forms a buffer solution. Reason : The solution after mixing contains a weak acid and its conjugate base and thus acts as buffer.A. If both the assertion and reason are true and reason is the true explanation of the assertion.B. If both the assertion and reason are true but the reason is not the correct explanation of assertion.C. If the assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - A `underset(0.05)underset(0.1)(NaCN)+underset(0)underset(0.05)(HCl) rarr underset(0.05)underset(0)(NaCl)+underset(0.05)underset(0)(HCN)` The solution contains a weak acid `HCN` and its conjugate base `CN^(-)` and thus acts as buffer. |
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| 138. |
Assertion : `0.20 M` solution of `NaCN` is more than basic than `0.20 M` solution of `NaF`. Reason : `K_(a)` of `HCN` is very much less than that of `HF`.A. Both assertion and reason are true and the reason is the correct explanation of the assertion.B. Both assertion and reason are true but reason is not the correct explanation of the assertion.C. Assertion is true but reason is false.D. Assertion is false but reason is true. |
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Answer» Correct Answer - A Since `K_(a)` of `HCN` is less than that of `HF`, so `CN_(-)` is stronger base than `F^(-)`. |
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| 139. |
Assertion (A): `BaCO_(3)` is more soluble in `HNO_(3)` than in water. Reason (R ): Carbonate is a weak base and reacts with `H^(o+)` ions to form strong acid causing barium salt to dissociate.A. If both assertion and reason are true and the reason is the correct explantion of the assertion.B. If both the assertion and reason are true and reason is not the correct explanation of assertion.C. If the assertion is true but reason is false.D. If the assertion and reason both are false. |
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Answer» Correct Answer - A Barium carbonate is more soluble in `HNO_(3)` than in water. Carbonate is a weak base and rects with the `H^(+)` ion of `HNO_(3)` causing the barium salt to dissociate. `BaCO_(3)+HNO_(3) rarr Ba(NO_(3))_(2)+CO_(2)+H_(2)O` |
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| 140. |
Which of the following has highest proton affinity?A. `NH_(3)`B. `PH_(3)`C. `H_(2)O`D. `H_(2)S` |
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Answer» Correct Answer - A `NH_(3)` is strongest base among them. |
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| 141. |
Assertion : The proton transfer reaction between `NH_(3)` and `H_(2)O` proceeds only to a slight extent. Reason : Proton transfer reaction is virtually complete in the case of `HCl` in dilute solution.A. If both assertion and reason are true and the reason is the correct explantion of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - B `NH_(3)` acts as weak base in aqueous solution. `HCl` acts as strong acid in aqueous solution. |
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| 142. |
Which of the following pairs consitutes buffer?A. `HNO_(3)` and `NH_(4)NO_(3)`B. `HCl` and `KCl`C. `HNO_(2)` and `NaNO_(2)`D. `NaOH` and `NaCl` |
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Answer» Correct Answer - C The mixture containing a weak acid `(HNO_(2))` and its conjugate base `(NO_(2)^(-))` acts as acidic buffer. |
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| 143. |
What is the `[OH^(-)]` in the final solution prepared by mixing `20.0 mL` of `0.050 M HCl` with `30.0 mL` of `0.10 M Ba(OH)_(2)`?A. `0.10 M`B. `0.40 M`C. `0.0050 M`D. `0.12 M` |
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Answer» Correct Answer - A Number of milleequivalent of `HCl` `=20xx0.050xx1=1` Number of millequivalent of `Ba(OH)_(2)` `=2xx30xx0.1=6` milliequivalent of `Ba(OH)_(2)` `[OH^(-)]` of final solution `=` (milliequivalent of `HCl`)/(total volume) `=(6-1)/(50)=0.1 M` |
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| 144. |
Which of these is least likely to act as Lewis base?A. `F^(-)`B. `BF^(3)`C. `PF^(3)`D. `CO` |
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Answer» Correct Answer - B `BF_(3)` is a Lewis acid (`e^(-)` pair acceptor). |
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| 145. |
Which of the following describes correct sequence for decreasing Lewis acid nature?A. `BCl_(3)gtBF_(3)gtBBr_(3)`B. `BBr_(3)gtBCl_(3)gtBF_(3)`C. `BBr_(3)gtBF_(3)gtBCl_(3)`D. `BF_(3)gtBCl_(3)gtBBr_(3)` |
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Answer» Correct Answer - B Due to back bonding `BF_(3)` shows maximum tendency due to small size of `F`. |
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| 146. |
Which of the following is least likely to behave as Lewis acid?A. `OH^(-)`B. `H_(2)O`C. `NH_(3)`D. `BF_(3)` |
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Answer» Correct Answer - D `BF_(3)` has incomplete octet and will act as Lewis acid. `NH_(3)` has lone pair of electron available for donaton and thus Lewis base. |
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| 147. |
Which of the following molecular hydride act as a Lewis acid ?A. `NH_(3)`B. `H_(2)O`C. `B_(2)H_(6)`D. `CH_(4)` |
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Answer» Correct Answer - A `B_(2)H_(6)` is electron deficient and can aceept lone pair of electrons. |
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| 148. |
Which of the following molecules acts as a Lewis acid?A. `(CH_(3))_(3)N`B. `(CH_(3))_(3)B`C. `(CH_(3))_(2)O`D. `(CH_(3))_(3)P` |
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Answer» Correct Answer - B It has sextet of electron and can accept lone pair of electron. |
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| 149. |
What is `[H^(+)]` in `mol//L` of a solution that is `0.20 M` in `CH_(3)COONa` and `0.1 M` in `CH_(3)COOH`? `K_(a)` for `CH_(3)COOH` is `1.8xx10^(-5)`?A. `3.5xx10^(-4)`B. `1.1xx10^(-5)`C. `1.8xx10^(-5)`D. `9.0xx10^(-6)` |
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Answer» Correct Answer - D `pH=pK_(a)+log``([Conjugate base])/([Acid])` `= -log1.8xx10^(-5)+log``(0.2)/(0.1)=5.045` `:. [H^(+)]=9.0xx10^(-6)` |
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The precipitate of `CaF_(2) (K_(sp)=1.7xx10^(-10))` is obtained when equal volumes of the following are mixedA. `10^(-4) M Ca^(2+) ion` and `10^(-4) M F^(-)`B. `10^(-2) M Ca^(2+)` and `10^(-3) M F^(-)`C. `10^(-5) M Ca^(2+)` and `10^(-3) M F^(-)`D. `10^(-3) M Ca^(2+)` and `10^(-5) M F^(-)` |
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Answer» Correct Answer - B `[Ca^(2+)]=(10^(-2))/(2)M` `[F^(-)]=(10^(-3))/(2)M` `I.P.=[Ca^(2+)][F^(-)]^(2)=((10^(-2))/(2))((10^(-3))/(2))^(2)=(10^(-8))/(8)` `I.P.gtK_(sp)` |
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