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 botany cell cycle difference between meiosis and mitosis division for growth and reproduction meiosis

........... is used for preparing standard solutions in which it is always desired to maintain a constant pH.

  1. Buffer

  2. Plasma

  3. Serum

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A buffer is a solution that resists a change in pH upon the addition of acidic or basic components. To effectively maintain a pH range, a buffer consists of a weak conjugate acid-base pair. It is either a weak acid and its conjugate base, or a weak base and its conjugate acid. Thus the correct answer is option A.

Multiple choice bio-chemistry digestive system of human digestive system- glands mouth and buccal cavity digestive glands

What is optimum pH for the action of salivary anylase?

  1. $1.8$
  2. $6.8$
  3. $7.4$
  4. $8$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The optimum pH for the enzymatic activity of salivary amylase ranges from 6 to 7. Above and below this range, the reaction rate reduces as enzymes get denaturated. The enzyme salivary amylase is most active at pH 6.8. 

So, the correct option is '6.8'.

Multiple choice evs water in our life where do we get water from? why conserve water uses of water

Which pH range is most conducive for fresh water plants and animals?

  1. 2.0 -3.5

  2. 3.5 -5.0

  3. 6.5 -7.5

  4. 8-9
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Most fresh water organisms thrive in a near-neutral pH range, typically between 6.5 and 7.5. Values significantly lower (acidic) or higher (alkaline) can be harmful to aquatic life.

Multiple choice chemistry electrolysis electrolytes and non-electrolytes introduction to electrolysis chemical reactions

The equivalent conductance at infinite dilution of an acid like HF

  1. Can be determined by extrapolation of measurements of dilute solutions of HCI, HBr and HI

  2. Can be determined by measurement of very dilute HF solution

  3. Can best be determined from measurements of concentrated solutions of NaF, NaCI and HCI

  4. Can best be determined from measurements of dilute solutions of NaF, NaCI and HCI.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The equivalent conductance at infinite dilution of an acid like $HF$ can best be determined from measurement of dilute solution of $NaF,NaCl,HCl$ because these have ionic character.

Multiple choice salts salts and their classification acids, bases and salts chemistry

${ H } _{ 3 }{ PO } _{ 4 }$ is a tribasic acid and one of its salt is $Na{ H } _{ 2 }{ PO } _{ 4 }$. What volume of 1M NaOH solution should be added to 12g $Na{ H } _{ 2 }{ PO } _{ 4 }$ to convert it into $Na _{ 3 }{ PO } _{ 4 }$? (at.wt of P=31)

  1. 100 mL

  2. 200 mL

  3. 80 mL

  4. 300 mL
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$NaH _2PO _4$ + $ 2 NaOH $ $ \rightarrow Na _3PO _4 + H _2O $

From the above reaction we can say that,
1 mol of $NaH _2PO _4$ reacts with 2 mol of NaOH.
Molar mass of $NaH _2PO _4$  = 120 g / mol
12g of $NaH _2PO _4$ contains = 0.1 mol
So the number of moles of NaOH required = 0.2 mol
Molarity of NaOH = 1M
1 mol = 1000 ml
0.2 mol = ?
So, the volume of 1M NaOH solution = 200 ml

Multiple choice salts salts and their classification acids, bases and salts chemistry

Equal volumes of $1\ M$ $HCl$ and $1\ M$ $H _2SO _4$ are neutralized by dilute NaOH solution liberating $x$ kcal and $y$ kcal heat. Which of the following is correct?

  1. $x=y$
  2. $x=0.5y$
  3. $x=0.4y$

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Reaction involved are:
$HCl+NaOH \rightarrow NaCl+H _2O, \Delta H _1=xkcal$
$H _2SO _4+2NaOH \rightarrow Na _2SO _4+2H _2O, \Delta H _1=ykcal$
(i) acid-base neutralization reaction for HCl is represented as:
$H^++OH^- \rightarrow H _2O, \Delta H _1=xkcal$
(ii) acid-base neutralization reaction for $H _2SO _4$ is represented as:
$2H^++2OH^- \rightarrow 2H _2O, \Delta H _1=ykcal$
since reaction (ii) is twice of reaction (i), so is the enthalpies
thus $2x=y$
or $x=0.5y$
Multiple choice salts salts and their classification acids, bases and salts chemistry

What is a titration curve?

  1. A graph of volume vs. pH for a titration.

  2. A graph of acid vs. base for a titration.

  3. A graph of acid vs. pH for a titration.

  4. A graph of volume vs. acid for a titration.

  5. A graph of base vs. pH for a titration.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A titration curve is a graph of volume of added base (or acid) vs. pH for a titration.

Multiple choice salts salts and their classification acids, bases and salts chemistry

What is titration?

  1. A technique used to analyze properties of solutions. It involves adding a titrant to the solution to be analyzed.

  2. A way to determine the concentration of an acid but not a base.

  3. A way to perform neutralization reactions.

  4. A way to determine the concentration of a base but not an acid.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Titration is a technique used to analyze properties of solutions (concentrations). It involves adding a titrant to the solution to be analyzed.
The process of adding one solution from the burette to another in the conical flask in order to complete the chemical reaction between the two solutions is known as titration. Of two solutions, one must be standard (of known concentration) and other must be of unknown strength.

Multiple choice salts salts and their classification acids, bases and salts chemistry

How do you determine the concentration of the unknown substance from the titration data?

  1. $(cH^+)(VH^+) = (cOH^-)(VOH^-)$
  2. $(cH^+)(VH^+) / (cOH^-)(VOH^-) = 1$
  3. $(cH^+)(VH^+) / (cOH^-)(VOH^-) = -log\:( pH)$
  4. $-log (cH^+)(VH^+) = pH$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

You determine the concentration of the unknown substance from the titration data by using the following equation
$\displaystyle  (cH^+)(VH^+) = (cOH^-)(VOH^-)$
$\displaystyle  (cH^+)  $  represents hydrogen ion concentration or acid concentration.
$\displaystyle   (VH^+) $ represents volume of acid solution.
$\displaystyle   (cOH^-)  $  represents hydroxide ion concentration (or base solution concentration).
$\displaystyle   (VOH^-)$  represents volume of base solution.

Multiple choice salts salts and their classification acids, bases and salts chemistry

Where does the equivalence point occur on a titration curve for a strong acid/strong base titration?

  1. At the endpoint, after pH 7.

  2. At pH 7, in the middle of the dramatic slope.

  3. At the very end of titration, between pH 10-12.

  4. Before the slope increases dramatically, between pH 2 and 4.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The equivalence point occur at pH 7, in the middle of the dramatic slope,
on a titration curve for a strong acid/strong base titration.
At the equivalence point, the salt of strong acid and strong base is completely hydrolyzed which gives a neutral solution with pH 7 as hydrogen ion concentration is equal to hydroxide ion concentration.