Chemistry

Solutions and pH Chemistry

451 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 chemistry the language of chemistry percent composition percentage composition and empirical formula empirical formula, percentage composition and molecular formula water of crystallisation

If the % composition of a 'x' component is 35%, find the mass of the dried 'x' component in 100g? mixture + beaker = 50 g, mass of beaker = 23 g

  1. 15.5 g

  2. 9.45 g

  3. 35.5 g

  4. 13.4 g
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

mass of beaker $= 23g$
mass of mix + beaker$ = 50g$
mass of mixture $= 50 - 23 = 27g$
$\%$ composition of mixture $= 35\%$
Mass of the x component $= 35 \times  \dfrac{27}{100} = 9.45g$

Multiple choice chemistry the language of chemistry percent composition percentage composition and empirical formula empirical formula, percentage composition and molecular formula water of crystallisation

If the % composition of Cl in HCl is 46%, what is the mass of Cl in HCl?

  1. 13.3 g

  2. 66 g

  3. 25 g

  4. 16.76 g
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\%$ $ composition =\cfrac{Mass \quad of\quad an \quad element.}{Total \quad mass \quad of\quad compound.}$

$Total \quad mass\quad of\quad HCl=1+35.5 g=36.5g$
$\therefore$ $\cfrac{46}{100}=\cfrac{mass\quad of\quad Cl}{36.5}\ mass\quad of\quad Cl=16.76g$

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.

Multiple choice botany cell theory, cell specialization, and cell replacement number and shape of cells unicellular and multicellular organisms diversity and classification in animals

A bacterium divides every 35 minutes . If a culture containing $ 10^5$ cell per ml is grown for 175 minutes. What will be the cell concentration per ml after 175 mts _______________.

  1. $32 \times 10^5$ cells
  2. $5 \times 10^5$ cells
  3. $35 \times 10^5$ cells
  4. $175 \times 10^5$ cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
It is given that a bacterium divides every 35 minutes,
At 0 minutes, the culture contains $ 10^5 $ cells/ml.
After 35 minutes, the culture will contain $ 2^1 \times 10^5 $ cells / ml
similarly, after 175 minutes, that is after 5 generations, the no. of cells
$ = 2^{5} \times 10^{5}$ cells/ml.
This is equal to $ 32 \times 10^{5} $ cell/ml
So, (A) is the correct answer.