Mix Examples - Acids, Bases and Salts Questions in English

(C) The poison of a honeybee is a complex mixture of various compounds.
One of the primary components responsible for the pain and inflammatory response is a peptide called $Melittin$.
$Melittin$ is the main constituent of bee venom, accounting for about $50\%$ of its dry weight.
It acts as a potent inflammatory agent and causes the release of histamine, leading to pain and swelling at the site of the sting.

(B) Molarity $(M)$ is defined as the number of moles of solute dissolved in $1 \ L$ of solution.
It is expressed as: $M = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}}$.
Molality is the number of moles of solute per kilogram of solvent.
Normality is the number of gram equivalents of solute per liter of solution.

(B) Molarity $(M)$ is defined as the number of moles of solute dissolved in one liter of solution.
The formula for molarity is: $M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}$.
Therefore,the unit of molarity is expressed as $\text{mole liter}^{-1}$ or $M$.

(B) Molarity $(M)$ is defined as the number of moles of solute per liter of solution.
The formula is: $M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}$.
Given:
Moles of solute = $1 \; mol$.
Volume of solution = $500 \; mL = 0.5 \; L$.
Calculation:
$M = \frac{1 \; mol}{0.5 \; L} = 2 \; mol/L = 2 \; M$.
Therefore,the molarity of the solution is $2 \; M$.

(B) The molecular mass of $NaOH$ is calculated by adding the atomic masses of its constituent elements:
Atomic mass of $Na = 23 \text{ u}$
Atomic mass of $O = 16 \text{ u}$
Atomic mass of $H = 1 \text{ u}$
Molecular mass of $NaOH = 23 + 16 + 1 = 40 \text{ g mol}^{-1}$.

(D) To calculate the molarity $(M)$,we use the formula: $M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}$.
First,calculate the molar mass of $NaOH$: $Na = 23, O = 16, H = 1$. So,$23 + 16 + 1 = 40 \ g/mol$.
Next,calculate the number of moles of $NaOH$: $\text{moles} = \frac{\text{given mass}}{\text{molar mass}} = \frac{8 \ g}{40 \ g/mol} = 0.2 \ mol$.
Convert the volume from $mL$ to $L$: $100 \ mL = 0.1 \ L$.
Finally,calculate molarity: $M = \frac{0.2 \ mol}{0.1 \ L} = 2 \ M$.
Therefore,the correct option is $D$.

(A) The concentration of a solution in Molarity $(M)$ is defined as the number of moles of solute dissolved per liter of solution.
Formula: $M = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}}$
Given:
Number of moles of solute = $1\;\text{mole}$
Volume of solution = $2\;\text{liters}$
Calculation:
$M = \frac{1\;\text{mole}}{2\;\text{liters}} = 0.5\;M$
Therefore,the concentration of the solution is $0.5\;M$.

(D) Antacids are basic substances used to neutralize excess acid in the stomach.
$Mg(OH)_{2}$ (Magnesium hydroxide),$Al(OH)_{3}$ (Aluminum hydroxide),and $NaHCO_{3}$ (Sodium bicarbonate) are all mild bases that react with excess $HCl$ in the stomach to neutralize it.
$HCl$ (Hydrochloric acid) is an acid itself,which is responsible for causing acidity in the stomach.
Therefore,$HCl$ cannot be used as an antacid.

(A) The $pH$ values of the given substances are as follows:
$1$. Vinegar is a dilute solution of acetic acid,which is acidic,so its $pH$ is approximately $2.5$.
$2$. Human blood is slightly basic,with a $pH$ range of approximately $7.35$ to $7.45$,so it matches $pH = 7.4$.
$3$. Washing soda $(Na_2CO_3)$ is a salt of a strong base and a weak acid,making its aqueous solution basic with a $pH$ of approximately $12$.
$4$. Pure water is neutral,so its $pH$ is $7.0$.
Therefore,the correct matching is $(1-b), (2-a), (3-d), (4-c)$.

(C) The chemical formulas for the given acids are as follows:
$1$. Sulphurous acid is $H_{2}SO_{3}$.
$2$. Sulphuric acid is $H_{2}SO_{4}$.
$3$. Oleum (also known as fuming sulphuric acid) is $H_{2}S_{2}O_{7}$.
$4$. Phosphoric acid is $H_{3}PO_{4}$.
Matching these with the given options:
$1-r, 2-s, 3-q, 4-p$.
Therefore, the correct option is $C$.

(B) Neutral oxides are those that do not react with either acids or bases. Common examples of neutral oxides include $N_{2}O$,$NO$,and $CO$.
$SO_{2}$ is an acidic oxide because it reacts with water to form sulfurous acid $(H_{2}SO_{3})$ and reacts with bases to form salts.
Therefore,$SO_{2}$ is not a neutral oxide.

(C) compound is a substance formed when two or more chemical elements are chemically bonded together.
Water is a chemical compound with the molecular formula $H_2O$.
It consists of two hydrogen atoms covalently bonded to one oxygen atom.
Ammonia $(NH_3)$ contains nitrogen and hydrogen.
Methane $(CH_4)$ contains carbon and hydrogen.
Hydrochloric acid $(HCl)$ contains hydrogen and chlorine.
Therefore,the correct option is $C$.

(C) Dihydrogen gas $(H_2)$ is a neutral gas.
Litmus paper is an acid-base indicator used to detect the presence of acidic or basic substances.
Since $H_2$ gas is neither acidic nor basic in nature,it does not change the color of either red or blue litmus paper.
Therefore,it has no effect on litmus paper.

(C) Ammonia $(NH_3)$ is a polar molecule that can form hydrogen bonds with water molecules.
Due to this ability to form strong hydrogen bonds,ammonia is extremely soluble in water.
In contrast,gases like $O_2$ are non-polar and have very low solubility in water.
Therefore,$NH_3$ is the correct answer.

(B) Sulfur dioxide $(SO_{2})$ acts as a mild bleaching agent due to its reducing property.
It bleaches colored matter by the removal of oxygen (reduction).
This bleaching effect is temporary because the bleached matter regains its color upon exposure to air due to atmospheric oxidation.

(C) When sulfur trioxide $(SO_{3})$ gas is absorbed in concentrated sulfuric acid $(H_{2}SO_{4})$,it forms oleum,which is also known as fuming sulfuric acid.
The chemical reaction is as follows:
$SO_{3} + H_{2}SO_{4} \rightarrow H_{2}S_{2}O_{7}$
$H_{2}S_{2}O_{7}$ is known as pyrosulfuric acid or oleum.

(B) Concentrated sulfuric acid $(H_{2}SO_{4})$ is typically defined as having a concentration of approximately $98\%$ by mass.
This means that in $100 \text{ g}$ of the solution,there are $98 \text{ g}$ of pure $H_{2}SO_{4}$ and $2 \text{ g}$ of water.
Therefore,the correct option is $B$.

(D) Dilute sulfuric acid is a solution where the concentration of $H_{2}SO_{4}$ is relatively low compared to the solvent (water).
Concentrated sulfuric acid typically contains about $98\%$ $H_{2}SO_{4}$ by mass.
Dilute sulfuric acid is prepared by adding concentrated acid to water,resulting in a significantly lower concentration,typically around $10\%$ to $20\%$ depending on the specific laboratory requirement.
Among the given options,$10\%$ is the most appropriate representation for dilute sulfuric acid.