Chemical Properties of Acids and Bases Questions in English

(C) Sulphurous acid is an inorganic compound with the chemical formula $H_{2}SO_{3}$.
It is formed when sulphur dioxide $(SO_{2})$ is dissolved in water $(H_{2}O)$.
The reaction is: $SO_{2} + H_{2}O \rightarrow H_{2}SO_{3}$.
In contrast,$H_{2}SO_{4}$ is sulphuric acid,$H_{2}S_{2}O_{7}$ is oleum,and $H_{2}SO_{2}$ is sulphoxylic acid.

(D) Phosphoric acid,also known as orthophosphoric acid,is a mineral acid with the chemical formula $H_{3}PO_{4}$.
It consists of one phosphorus atom,four oxygen atoms,and three hydrogen atoms.
Therefore,the correct option is $D$.

(B) When a glass rod dipped in concentrated hydrochloric acid $(HCl)$ is brought near ammonia gas $(NH_3)$,they react to form ammonium chloride $(NH_4Cl)$ solid particles.
The chemical equation for this reaction is: $NH_3(g) + HCl(g) \rightarrow NH_4Cl(s)$.
These solid particles of ammonium chloride appear as dense white fumes.

(D) Nitric acid is a strong mineral acid with the chemical formula $HNO_{3}$.
It is a colorless,fuming liquid that is highly corrosive and toxic.
In the given options,$HNO_{2}$ represents nitrous acid,$NH_{4}Cl$ represents ammonium chloride,and $H_{2}NO_{3}$ is not a standard chemical formula for a stable acid.

(D) Ammonium hydroxide $(NH_4OH)$ is a solution of ammonia $(NH_3)$ in water.
It dissociates only partially in an aqueous solution to produce ammonium ions $(NH_4^+)$ and hydroxide ions $(OH^-)$.
Because it does not ionize completely,it is classified as a weak base.

(C) dehydrating agent is a substance that removes water from another compound or mixture.
Concentrated sulfuric acid $(H_2SO_4)$ is a very strong dehydrating agent because it has a high affinity for water.
It can remove water molecules from various organic compounds,such as sugar $(C_{12}H_{22}O_{11})$,leaving behind carbon.
Therefore,concentrated sulfuric acid is widely used in laboratories for this purpose.

(B) dibasic acid is an acid that contains two replaceable hydrogen atoms per molecule.
$1$. Hydrochloric acid $(HCl)$ is monobasic as it provides one $H^+$ ion.
$2$. Sulphuric acid $(H_2SO_4)$ is dibasic as it provides two $H^+$ ions per molecule upon dissociation $(H_2SO_4 \rightarrow 2H^+ + SO_4^{2-})$.
$3$. Nitric acid $(HNO_3)$ is monobasic as it provides one $H^+$ ion.
$4$. Hydrobromic acid $(HBr)$ is monobasic as it provides one $H^+$ ion.
Therefore,the correct answer is $H_2SO_4$.

(C) The formation of curd from milk is a fermentation process carried out by Lactic Acid Bacteria $(LAB)$,such as Lactobacillus.
During this process,the bacteria convert the milk sugar,known as lactose,into lactic acid.
This increase in acidity causes the milk proteins (casein) to coagulate,resulting in the thickening of milk into curd.