An acid-base indicator which is a weak acid has a `pK_(In)` value =5.45. At what concentration ratio of sodium acetate to acctic acid would the indicator show a colour half-way between those of its acid and conjugate base forms ? `[pK_(a)` of acetic acid =4.75, log 2=0.3]
What is the pH of a solution of 0.28 M acid and 0.84 M of its conjugate base if the ionization constant of acid is 4xx10^(-4) ?
What is the pOH of 0.1 M KB (salt of weak acid and strong base) at 25^(@)C ? (Given : pK_(b) of B^(-) =7)
Acid-base indicators are either weak organic acids or weak organic bases. Indicator change colour in dilute solution when the hydonium ion concentration reaches a particular calur For example. Phenolphthalein is a coloureless stbstance in any aqueous solution with a pH less than 8.3 In between the pH range 8.3 to 10, transition of colour (colourless to pink ) takes place and if pH of solution is greater than 10 solution is dark pink. Considering an acid indicator Hln, the equilibrium involving it and its conjgate base In^(-) can be represented as : " " underset("acidic from")(HIn)hArrH^(+)underset("basic from")(In^(-)) pH of solution can be computed as : " " pH=pK_(In)+log.([IN^(-)])/([HIn]) In general, transition of colour takes place in between the pH range pK_(In+-1. Select the correct statement (s) :
An acid-base indicator has a K_(a) of 3.0 xx 10^(-5) . The acid form of the indicator is red and the basic form is blue. (a) By how much must the pH change in order to change the indicator from 75% red to 75% blue?
In the titration of solution of a weak acid HA and NaOH, the pH is 5.0 after 10 mL of NaOH solution has been added and 5.60 after 20 mL NaOH has been added. What is the value of pK_(a) for HA?
Fixed volume of 0.1 M benzoic acid (pK_(a)=4.2) solution is added into 0.2 M sodium benzoate solution and formed a 300 mL, resultant acidic buffer solution. If pH of this buffer solution is 4.5 then find added volume of benzoic acid :
Calcium lactate is a salt of weak organic acid and strong base represented as Ca(LaC)_(2). A saturated solution of Ca(LaC)_(2) contains 0.13 mole in 0.5 litre solution. pOH of solution is 5.60. What is pK_(a) of lactic acid?
Morphine (C_(17)H_(19)NO_(3)), Which is used medically to relieve to pain is a base. What is its conjugate acid?
The conductivity of 0.001028 mol L^(-1) acetic acid is 4.95 xx 10^-5 S cm^-1 . Calculate its dissociation constant if A_m^@ for acetic acid is 390.5 S cm^2 mol^(-1).
Choose the correct set of True/Fasle for following statements: (i) Silver chloride is more soluble in very concentrated sodium chloride solution than in pure water. (ii) The pH of a buffer solution does not change on addition of small amount of an acid or a base. (iii) Addition of NH_(4)Cl does not affect the pH of a solution of NH_(4)OH (iv) Degree of hydrolysis of ammonium acetate does not depend upon the concentration of ammonium acetate solution. (v) A mixture of acetic acid and sodium acetate can act as buffer solution.
NARENDRA AWASTHI-IONIC EEQUILIBRIUM-Assertin-Reason Type Questions
