Chemical Properties of Acids and Bases Questions in English

(N/A) When an acid reacts with a metal,$Hydrogen$ gas is liberated.
Example: When $Zinc$ granules react with dilute $Hydrochloric$ acid $(HCl)$,$Zinc$ chloride $(ZnCl_{2})$ and $Hydrogen$ gas $(H_{2})$ are produced.
$Zn(s) + 2HCl(aq) \longrightarrow ZnCl_{2}(aq) + H_{2}(g)$
Test for $Hydrogen$ gas: Bring a burning candle or a matchstick near the mouth of the test tube containing the gas. The gas burns with a characteristic '$pop$' sound,which confirms the presence of $Hydrogen$ gas.

(N/A) The substance $'X'$ is lime water,which is calcium hydroxide $\left[ Ca(OH)_{2} \right]$.
The chemical equation for the reaction of lime water with carbon dioxide is:
$Ca(OH)_{2}(aq) + CO_{2}(g) \longrightarrow CaCO_{3}(s) + H_{2}O(l)$
$(b)$ $'X'$ (calcium hydroxide) is obtained by the reaction of quick lime (calcium oxide) with water (slaking of lime).
The chemical equation is:
$CaO(s) + H_{2}O(l) \longrightarrow Ca(OH)_{2}(aq)$

(N/A) Tap water contains various dissolved salts that dissociate into ions when electricity is passed through it. These ions act as charge carriers,allowing the flow of electricity. In contrast,distilled water is pure and does not contain any dissolved salts or ions,making it an insulator that does not conduct electricity.

(N/A) Dry hydrogen chloride gas does not contain $H^{+}$ ions. Acids exhibit acidic properties only in the presence of water because they dissociate to produce hydrogen ions $H^{+}(aq)$. Since dry $HCl$ gas lacks water,it cannot release $H^{+}$ ions,and therefore,it does not show acidic behavior or change the color of blue litmus paper.

(C) weak acid is an acid that partially dissociates into its ions in an aqueous solution.
$H_2SO_4$ (Sulphuric acid),$HNO_3$ (Nitric acid),and $HCl$ (Hydrochloric acid) are strong acids because they dissociate completely in water.
$CH_3COOH$ (Ethanoic acid or Acetic acid) is a weak acid because it only partially dissociates in water,resulting in a lower concentration of $H^+$ ions.

(D) Mineral acids are acids derived from inorganic compounds,typically non-living sources.
Citric acid,Lactic acid,and Oxalic acid are organic acids found in plants and animals.
Nitric acid $(HNO_3)$ is a mineral acid prepared from inorganic minerals.
Therefore,the correct option is $D$.

(A) Oxalic acid is a dicarboxylic acid found in various plants.
Among the given options,tomato contains oxalic acid.
Orange contains citric acid,sour milk contains lactic acid,and tamarind contains tartaric acid.

(A) When carbon dioxide $(CO_2)$ is dissolved in water under high pressure,it reacts with water to form carbonic acid $(H_2CO_3)$.
The chemical equation for this reaction is:
$CO_2(g) + H_2O(l) \rightarrow H_2CO_3(aq)$

(C) Hydrochloric acid $(HCl)$ is a strong acid that dissociates completely in an aqueous solution.
The dissociation reaction is represented as: $HCl + H_{2}O \rightarrow H_{3}O^{+} + Cl^{-}$.
In a dilute aqueous solution,$HCl$ exists primarily as hydronium ions $(H_{3}O^{+})$ and chloride ions $(Cl^{-})$.
Therefore,the correct species present are $H_{3}O^{+}$ and $Cl^{-}$.

(FALSE) False.
Acids like $HCl$ show acidic character only in the presence of water because water is required to dissociate $HCl$ molecules into $H^+$ (or $H_3O^+$) ions and $Cl^-$ ions.
In the absence of water,$HCl$ exists as covalent molecules and does not release $H^+$ ions,thus it does not exhibit acidic properties.

(TRUE) The statement is True.
According to the Arrhenius theory of acids,an acid is a substance that dissociates in water to produce hydrogen ions $(H^{+})$. Since $H^{+}$ ions are highly reactive and cannot exist independently in an aqueous solution,they immediately combine with water molecules $(H_{2}O)$ to form hydronium ions $(H_{3}O^{+})$.
Therefore,the reaction is represented as: $HCl + H_{2}O \rightarrow H_{3}O^{+} + Cl^{-}$.
Thus,acids produce $H_{3}O^{+}$ or $H^{+}(aq)$ ions in water.

(TRUE) True.
When an acid or a base is dissolved in water,it releases a significant amount of heat energy. This reaction is known as an exothermic process. Because of this,it is always recommended to add acid to water slowly with constant stirring,rather than adding water to a concentrated acid,to prevent the mixture from splashing out due to the sudden release of heat.

(B) The statement is False.
When diluting concentrated acids,the process is highly exothermic,meaning it releases a large amount of heat.
If water is added to concentrated acid,the heat generated may cause the mixture to splash out and cause severe acid burns.
Therefore,the correct procedure is to always add the concentrated acid slowly to a large volume of water with constant stirring,not the other way around.

(FALSE) The statement is False.
When an acid or a base is mixed with water,it undergoes a process called dilution.
Dilution is the process of adding water to a concentrated acid or base,which results in a decrease in the concentration of ions $(H_{3}O^{+}$ for acids or $OH^{-}$ for bases) per unit volume.
Therefore,the concentration of ions per unit volume decreases,not increases.

(C) Non-metal oxides are acidic in nature. When a non-metal oxide reacts with a base,it undergoes a neutralization reaction to produce salt and water. For example,the reaction between carbon dioxide $(CO_2)$,which is a non-metal oxide,and calcium hydroxide $(Ca(OH)_2)$,which is a base,produces calcium carbonate $(CaCO_3)$ and water $(H_2O)$: $Ca(OH)_2 + CO_2 \rightarrow CaCO_3 + H_2O$. Therefore,the correct product formed is a salt.

(B) When an acid reacts with a metal oxide,it undergoes a neutralization reaction to form salt and water.
Metal oxides are basic in nature.
Therefore,the general chemical equation is: $\text{Acid} + \text{Metal oxide} \longrightarrow \text{Salt} + \text{Water}$.
For example: $2HCl + CuO \longrightarrow CuCl_2 + H_2O$.

(B) Distilled water is pure water $(H_2O)$ and does not contain dissolved salts or ions.
Since electricity requires free ions or electrons to flow through a medium,the absence of these charge carriers makes distilled water a poor conductor of electricity.
Therefore,distilled water acts as an insulator.

(B) Solutions that conduct electricity are known as electrolytes. These substances dissociate into ions when dissolved in water,allowing the flow of electric current through the solution.

(B) An antacid is a substance that neutralizes stomach acidity.
$Mg(OH)_{2}$,also known as milk of magnesia,is a mild base used as an antacid to treat indigestion and heartburn by neutralizing excess $HCl$ in the stomach.
$NaCl$ is a neutral salt.
$HCl$ and $H_{2}SO_{4}$ are strong acids.

(D) $NH_{3}$ (Ammonia) is a weak base because it does not completely dissociate into ions in an aqueous solution. When it reacts with water,it accepts a proton $(H^{+})$ to form ammonium $(NH_{4}^{+})$ and hydroxide $(OH^{-})$ ions,but this reaction is reversible and does not go to completion. Therefore,it is classified as a weak base.

(A) Lemon juice contains citric acid,which is a weak organic acid.
When lemon juice is dissolved in water,it releases hydrogen ions $(H^+)$,which makes the aqueous solution acidic in nature.
Therefore,the correct option is $A$.

(D) Robert Boyle was the first scientist to define acids and bases based on their chemical properties. He observed that acids have a sour taste,change the color of litmus from blue to red,and react with metals to release hydrogen gas. Bases,on the other hand,were defined by their bitter taste,soapy feel,and ability to turn red litmus blue.

(B) The properties of acids are as follows:
$1$. Acids are sour to taste.
$2$. Acids turn blue litmus paper red,not red litmus paper blue. Turning red litmus paper blue is a property of bases.
$3$. Acids react with bases to form salt and water,which is known as a neutralization reaction.
$4$. Acids react with active metals to release $H_{2}$ gas.
Therefore,the statement 'They turn moist red litmus paper blue' is incorrect.

(A) Acids are substances that release $H^+$ ions in an aqueous solution.
According to the chemical properties of acids,they have the ability to change the color of blue litmus paper to red.
This reaction occurs because the acidic nature of the solution neutralizes the basic dye present in the litmus paper,resulting in a color change to red.
Therefore,moist blue litmus paper turns red in the presence of an acid.

(D) When an acid reacts with a base, the hydrogen ions $(H^+)$ from the acid combine with the hydroxide ions $(OH^-)$ from the base to form water $(H_2O)$.
The remaining ions form a salt.
This process is known as a neutralisation reaction.
The general equation is: $\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}$.

(B) When an acid reacts with a metal,it produces a metal salt and releases $H_2$ gas.
For example,the reaction between zinc and dilute hydrochloric acid is:
$Zn(s) + 2HCl(aq) \rightarrow ZnCl_2(aq) + H_2(g)$
Therefore,the gas released is dihydrogen $(H_2)$.

(C) The acid-base theory of ionization was proposed by Svante Arrhenius in $1884$.
According to the Arrhenius theory,an acid is a substance that dissociates in water to produce hydrogen ions $(H^+)$,and a base is a substance that dissociates in water to produce hydroxide ions $(OH^-)$.
Therefore,the correct option is $C$.

(C) According to the Arrhenius theory,a base is defined as a substance that dissociates in water to produce hydroxide ions $(OH^-)$ as the only negative ions.
For example,sodium hydroxide $(NaOH)$ dissociates in water as follows:
$NaOH(aq) \rightarrow Na^+(aq) + OH^-(aq)$
Therefore,the correct option is $C$.

(B) Acids produce hydrogen ions $(H^{+})$ in the presence of water. Since $H^{+}$ ions cannot exist alone,they combine with water molecules $(H_{2}O)$ to form hydronium ions $(H_{3}O^{+})$.
Therefore,the reaction is: $H^{+} + H_{2}O \rightarrow H_{3}O^{+}$.
Thus,$H_{3}O^{+}$ is known as the hydronium ion.

(B) According to the Arrhenius theory,an acid is a substance that dissociates in water to increase the concentration of hydrogen ions $(H^{+})$.
When an acid is dissolved in water,it releases $H^{+}$ ions,which immediately combine with water molecules to form hydronium ions $(H_{3}O^{+})$.
However,the fundamental definition states that acids produce $H^{+}$ ions in aqueous solution.

(A) Caustic soda is the common name for sodium hydroxide, which has the chemical formula $NaOH$.
When $NaOH$ is dissolved in water, it undergoes complete ionization to produce sodium ions $(Na^+)$ and hydroxide ions $(OH^-)$.
The dissociation reaction is represented as: $NaOH_{(s)} \xrightarrow{H_2O} Na^+_{(aq)} + OH^-_{(aq)}$.
Therefore, the ions produced are $Na^+_{(aq)}$ and $OH^-_{(aq)}$.

(B) The Bronsted-Lowry theory,proposed independently by Johannes Nicolaus Bronsted and Thomas Martin Lowry in $1923$,defines an acid as a proton $(H^+)$ donor and a base as a proton $(H^+)$ acceptor. Therefore,the fundamental basis of this theory is the transfer of protons between chemical species.

(C) The $Bronsted-Lowry$ theory defines an acid as a proton $(H^+)$ donor and a base as a proton $(H^+)$ acceptor.
Unlike the $Arrhenius$ theory,which is limited to aqueous solutions where $H^+$ or $OH^-$ ions are produced,the $Bronsted-Lowry$ theory does not require water as a solvent.
Therefore,it can be applied to both aqueous and non-aqueous solutions,as well as gas-phase reactions.

(D) According to the Bronsted-Lowry theory,an acid is a proton $(H^{+})$ donor.
When an acid is dissolved in water,it releases a proton $(H^{+})$.
Since a proton $(H^{+})$ cannot exist independently in an aqueous solution,it immediately reacts with a water molecule $(H_{2}O)$ to form a hydronium ion $(H_{3}O^{+})$.
Therefore,the acidity of an aqueous solution is due to the presence of hydronium ions $(H_{3}O^{+})$.

(A) The hydronium ion $(H_{3}O^{+})$ is formed when a water molecule $(H_{2}O)$ acts as a Lewis base and donates a lone pair of electrons to a hydrogen ion $(H^{+})$,which acts as a Lewis acid.
In a water molecule,the oxygen atom has two lone pairs of electrons.
One of these lone pairs is donated to the $H^{+}$ ion to form a coordinate covalent bond (also known as a dative bond).
Therefore,the coordinate covalent bond exists between the oxygen atom of the $H_{2}O$ molecule and the $H^{+}$ ion.

(C) According to the Bronsted-Lowry theory,an acid is defined as a substance that acts as a proton $(H^+)$ donor.
Conversely,a base is defined as a substance that acts as a proton $(H^+)$ acceptor.
Therefore,the substance that donates a proton to another substance is classified as an acid.

(B) According to the Bronsted-Lowry theory:
$1$. An acid is defined as a proton $(H^+)$ donor.
$2$. $A$ base is defined as a proton $(H^+)$ acceptor.
Since the question asks for a substance that accepts a proton from another substance,it is classified as a base.

(C) According to the $Brønsted-Lowry$ theory, an acid is defined as a substance that can donate a proton ($H^+$ ion), while a base is defined as a substance that can accept a proton ($H^+$ ion).
Therefore, a base is a proton acceptor.

(A) When hydrogen chloride $(HCl)$ gas is dissolved in water $(H_2O)$,it undergoes ionization to form hydronium ions $(H_3O^+)$ and chloride ions $(Cl^-)$.
The reaction is: $HCl + H_2O \rightarrow H_3O^+ + Cl^-$.
In this reaction,$HCl$ acts as a Brønsted-Lowry acid by donating a proton $(H^+)$ to the water molecule.
Water acts as a Brønsted-Lowry base by accepting the proton from $HCl$.

(B) When carbon dioxide $(CO_2)$ reacts with water $(H_2O)$,it forms carbonic acid $(H_2CO_3)$.
The chemical equation for this reaction is: $CO_2 + H_2O \rightarrow H_2CO_3$.
Carbonic acid is a weak acid formed when carbon dioxide dissolves in water.

(C) When an acid reacts with a base, a neutralization reaction occurs.
In this reaction, the acid and base neutralize each other to produce salt and water.
The general chemical equation is: $\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}$.

(B) $NaOH$ stands for Sodium Hydroxide.
It is a chemical compound that dissociates completely in water to produce hydroxide ions $(OH^-)$.
Because it ionizes completely in an aqueous solution,it is classified as a strong base.

(D) When an acid reacts with a metal carbonate or a metal hydrogen carbonate,it produces a corresponding salt,water,and carbon dioxide gas.
The general chemical equation is:
Metal Carbonate/Hydrogen Carbonate + Acid $\rightarrow$ Salt + Water + Carbon Dioxide $(CO_2)$
For example,the reaction of sodium carbonate $(Na_2CO_3)$ with hydrochloric acid $(HCl)$:
$Na_2CO_3(s) + 2HCl(aq) \rightarrow 2NaCl(aq) + H_2O(l) + CO_2(g)$
Therefore,the gas released is carbon dioxide.

(C) Bases are substances that dissociate in aqueous solutions to produce hydroxyl ions $(OH^{-})$.
These $OH^{-}$ ions are responsible for the characteristic chemical properties of bases,such as their bitter taste,soapy feel,and ability to react with acids to form salt and water (neutralization reaction).

(A) Bases are substances that dissociate in water to produce hydroxyl ions $(OH^-)$.
These $OH^-$ ions are responsible for the characteristic chemical properties of bases,such as their bitter taste,soapy feel,and ability to react with acids to form salt and water (neutralization reaction).
In contrast,acids are responsible for producing hydronium ions $(H_3O^+)$ in aqueous solutions.

(D) When a red ant bites,it injects an acidic liquid into the skin.
This liquid contains $Formic \ acid$ (also known as $Methanoic \ acid$,with the chemical formula $HCOOH$).
This acid causes irritation,pain,and a burning sensation at the site of the bite.
Therefore,the correct option is $D$.

(C) $H_{2}SO_{4}$ is a strong diprotic acid that dissociates completely in an aqueous solution according to the following equation:
$H_{2}SO_{4} \rightarrow 2H^{+} + SO_{4}^{2-}$
Since $H^{+}$ ions react with water to form hydronium ions $(H_{3}O^{+})$,the reaction can be represented as:
$H_{2}SO_{4} + 2H_{2}O \rightarrow 2H_{3}O^{+} + SO_{4}^{2-}$
From the stoichiometry of the reaction,$1$ mole of $H_{2}SO_{4}$ produces $2$ moles of $H_{3}O^{+}$.
Therefore,for a $1\,M$ solution of $H_{2}SO_{4}$,the concentration of $H_{3}O^{+}$ will be $2 \times 1\,M = 2\,M$.

(B) $H_{2}SO_{4}$ (Sulfuric acid) is known as 'the king of chemicals'.
This is because it is used extensively in various industrial processes,including the manufacturing of fertilizers,dyes,pigments,detergents,and explosives.
It is also a vital component in lead-acid batteries used in automobiles.

(D) $H_{2}O$ (water) is a neutral oxide. It does not change the color of red or blue litmus paper,indicating that it is neither acidic nor basic in nature. It acts as a solvent and can react with both acids and bases depending on the conditions,but it is classified as a neutral oxide.

(A) When sulfur dioxide $(SO_{2})$ reacts with water $(H_{2}O)$,it forms sulfurous acid $(H_{2}SO_{3})$.
The chemical equation for this reaction is: $SO_{2} + H_{2}O \rightarrow H_{2}SO_{3}$.
Sulfurous acid is a weak acid formed by the dissolution of sulfur dioxide in water.