Chemistry

Solutions and pH Chemistry

400 Questions

Solutions and pH chemistry focus on the acidity or alkalinity of various substances, from human urine to acidic soils. Questions involve titration calculations, molarity determination, and understanding mole fractions. This topic is a staple in the chemistry sections of state and national level competitive exams.

Calculating solution molarityMole fraction calculationpH value interpretationAcidic soils and pHTitration and neutralization

Solutions and pH Chemistry Questions

Multiple choice action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

If the pH of an alkali metal hydroxide is 13.6, the concentration of hydroxide is ;

  1. More than 1 M

  2. Between 0.1 M and 1 M

  3. Between 0.01 M and 1 M

  4. Less than 0.001 M
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Given that :

$pH = 13.6$

Thus, $pOH = 14 - 13.6$

                     $=0.4$
Hence,
$[O{H^ - }] = lo{g^{ - 1}}( - 0.4)$

               $ = 0.3979$

Therefore the value of $[O{H^ - }]$ is between $0.1M$ and $1M$.

Therefore, the option is B.

Multiple choice chemistry chemical reactions of organic compounds uses of alcohols commercially important alcohols - ethanol some commercially important alcohols commercially important alcohols - methanol methanol

Write the balanced equation for the following :-
Bromoethane and an aqueous solution of sodium hydroxide.

  1. $C _2H _5Br+NaOH\rightarrow C _2H _6$
  2. $C _2H _5Br+NaOH\rightarrow C _2H _5OH$
  3. $C _2H _5Br+NaOH\rightarrow C _2H _4O$
  4. $C _2H _5Br+NaOH\rightarrow C _2H _2O$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reaction:
$C _2H _5Br+NaOH\rightarrow C _2H _5OH$

Multiple choice chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

Vinegar is a :

  1. 5-8% solution of acetic acid in water

  2. 25-30% solution of acetic acid in water

  3. 40-45% solution of acetic acid in water

  4. 45-50% solution of acetic acid in water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vinegar is a liquid containing acetic acid and water. This acetic acid is produced by the fermentation of ethanol by acetic acid bacteria. It is mainly used as a cooking ingredient. It is a 5-8% solution of acetic acid in water and most easily available mild acid.

Multiple choice chemistry reaction kinetics determining rates graphically calculating rate of reaction graphically rate of a chemical reaction

An aqueous solution of $CH _3COOH$ has a pH = $3$ and acid dissociation constant of $CH _3COOH$ is $10^{-5}$. What will be the concentration of acid taken initially?

  1. $0.1$M
  2. $0.11$M
  3. $0.09$M
  4. $0.101$M
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

${H}^{+} = \sqrt{{K} _{a} \times {C}}$


${10}^{-6} = {10}^{-5} \times {C}$

${C} = 0.1\space M$

Multiple choice hydrogen ion scale or the ph scale inorganic analysis chemical analysis and investigation practical work chemistry

pH stands for :

  1. power of hydrogen

  2. power of hydroxide

  3. purity of hydrogen

  4. purity of hydroxide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

pH is the negative log of hydrogen ion concentration in a water-based solution. The term 'pH' was first described by Danish biochemist Soren Peter Lauritz Sorensen in 1909. pH is an abbreviation for 'power of hydrogen' where 'p' is short for the German word for power and 'H' is the element symbol for hydrogen.

Multiple choice hydrogen ion scale or the ph scale inorganic analysis chemical analysis and investigation practical work chemistry


$\begin{matrix}&pH=X\Cr _2O _7^{2-}&\rightleftharpoons&CrO _4^{2-}\(orange)&pH=Y&(green)\end{matrix}$
This change is based on change in $pH$. Probable values of $X$ and $Y$ cannot be :

  1. 8, 6

  2. 8, 10

  3. 4, 6
  4. change is independent of $pH$
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

$\begin{matrix}&pH=X= 8  \ or \ 4 \ (less\  than \ Y) \Cr _2O _7^{2-}&\rightleftharpoons&CrO _4^{2-}\orange&pH=Y= 10\  or \ 6  \ (more\  than\  X) &green\end{matrix}$

As dichromate ion changes to chromate in acidic medium( less pH) , whereas chromate changes to dichromate in basic medium ( higher pH)
                             Lower pH (acidic medium) $\rightarrow$
$ Cr _2O _7^{2-}<========================>CrO _4^{2-}$
                            $\leftarrow$ Higher pH ( basic medium)

Multiple choice hydrogen ion scale or the ph scale inorganic analysis chemical analysis and investigation practical work chemistry

$\displaystyle \underset {orange}{Cr _2O _7^{2-}}\,\overset {pH=x}{ \underset {pH = y}{\leftrightarrows}}\, \underset {green}{CrO _4^{2-}}$. 


This change is based on change in pH. 

Find values of x and y  :

  1. $8, 6$
  2. $8, 10$
  3. $4, 6$

  4. change is independent of pH
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The process involves the equilibrium between chromate (VI), dichromate (VI) and hydrogen ions:


$2{ Cr{ O } _{ 4 }^{ 2- } } _{ \left( aq. \right)  \left( yellow \right)  }+2{ { H }^{ + } } _{ \left( aq. \right)  }\rightleftharpoons { { Cr } _{ 2 }{ O } _{ 7 }^{ 2- } } _{ \left( aq. \right)  \left( orange \right)  }+{ { H } _{ 2 }O } _{ \left( l \right)  }$

The addition of acid encourages the equilibrium towards the right (pH=6), producing more orange colored dichromate (VI) ions. The addition of hydroxide ions causes the concentration of hydrogen ions to decrease, and this brings the equilibrium back to the left-hand side, regenerating yellow chromate (VI) ions.