Acid Base And Salt Quiz Questions And Answers

A pH value of 9 corresponds to a basic solution. The pH scale ranges from 0 to 14, with values below 7 indicating acidity, 7 being neutral, and values above 7 indicating alkalinity or basicity. Therefore, a pH value of 9 falls on the alkaline side of the scale, indicating that the solution is basic.

The statement is false because the more acidic a solution is, the lower its pH value will be. pH is a measure of the concentration of hydrogen ions in a solution, and as the concentration of hydrogen ions increases, the acidity of the solution increases and the pH value decreases. Therefore, a higher acidity corresponds to a lower pH value.

Hydrochloric acid will dissociate completely in an aqueous solution because it is a strong acid. Strong acids are those that completely dissociate into ions when dissolved in water. Hydrochloric acid, with the chemical formula HCl, is a strong acid that ionizes into H+ and Cl- ions in water. This complete dissociation allows it to readily react with other substances in the solution. In contrast, carbonic acid, acetic acid, and formic acid are weak acids that only partially dissociate in water.

An efflorescent salt is a hydrated salt that loses its water to the atmosphere. This means that the salt contains water molecules within its crystal structure, but when exposed to air, the water evaporates, leaving behind the anhydrous form of the salt. This process is known as efflorescence.

H2SO4 is a dibasic acid because it has two ionizable hydrogen atoms. Dibasic acids are capable of donating two hydrogen ions in solution. In H2SO4, both hydrogen atoms can be ionized to form H+ ions, making it a dibasic acid. HCOOH, HNO3, and HNO2 are all monobasic acids because they only have one ionizable hydrogen atom.

 Barium sulfate and lead (II) sulfate are the correct pair of insoluble sulfates. When these two compounds are mixed in water, they do not dissolve and form a precipitate. This is due to the low solubility of both compounds in water. The insolubility of these sulfates can be attributed to the strong ionic bonds present in their crystal structures, which make it difficult for them to break apart and dissolve in water. Therefore, when barium sulfate and lead (II) sulfate are mixed in water, they remain as solid particles, indicating their insolubility.

Copper hydroxide is not an alkali because it does not belong to the group of alkali metals. Alkali metals include elements such as sodium and potassium, which form hydroxides that are highly basic and soluble in water. Copper hydroxide, on the other hand, is a transition metal compound that is less basic and less soluble in water compared to alkali metal hydroxides.

When ammonium salt is added to a solution with pH-13 and gently heated, it will liberate a basic gas. This gas is capable of reacting with HCl, producing dense white fumes. This observation indicates that the gas is alkaline in nature. Therefore, the correct answer is that it will liberate basic gas, which gives dense white fume when a rod dipped in HCl is brought near it.

When litmus paper is dipped in an ammonium sulfate solution, a color change is observed. Litmus paper is typically blue in its natural state, but when it comes into contact with an acidic substance like ammonium sulfate, it turns red. This is because litmus paper is a pH indicator and changes color depending on the acidity or alkalinity of the solution it is exposed to. In this case, the ammonium sulfate solution is acidic, causing the litmus paper to turn red.

The statement "The solution of a salt of a weak acid and a strong base is neutral" is incorrect. When a weak acid reacts with a strong base to form a salt, the resulting solution is usually slightly basic. This is because the weak acid does not completely dissociate, and some of the conjugate base from the weak acid remains in the solution, making it slightly basic. Therefore, the correct answer is "The solution of a salt of a weak acid and a strong base is alkaline."

Calcium hydroxide is a diacidic base because it can donate two hydroxide ions (OH-) when it reacts with an acid. This property makes it capable of neutralizing two moles of acid per mole of calcium hydroxide. Sodium hydroxide, potassium hydroxide, and ammonium hydroxide are all monobasic bases, meaning they can donate only one hydroxide ion.

The statement is false because in an acid, the acidic hydrogen is bonded to an atom that is more electronegative than itself. This is because acids are substances that can donate protons (H+ ions), and the hydrogen atom in an acid is typically bonded to an electronegative atom such as oxygen or a halogen. The electronegativity difference between the hydrogen and the electronegative atom creates a polar bond, allowing the acidic hydrogen to be easily released as a proton.

Tribasic acid forms one normal and two acidic salts because it has three replaceable hydrogen atoms. When all three hydrogen atoms are replaced by metal ions, a normal salt is formed. However, when only one or two hydrogen atoms are replaced, acidic salts are formed. Therefore, the correct answer is one normal and two acidic salts.

H3PO4 can form two acid salts because it has three acidic hydrogen atoms. When one or two of these hydrogen atoms are replaced by a metal, such as sodium or potassium, two different acid salts can be formed. This is because each replacement of a hydrogen atom creates a different compound with unique properties and characteristics.

The given statement accurately describes a universal indicator. Universal indicators are compounds that exhibit different colors at different pH values, allowing them to be used to determine the acidity or alkalinity of a solution. Methyl orange, on the other hand, is a specific acid-base indicator that changes color at a specific pH range, not a universal indicator.

Strong acids completely ionize in solution, releasing all their hydrogen ions (H+). Hydrochloric acid is a strong acid because it dissociates completely into H+ and Cl- ions when dissolved in water. The other options are either weak acids (partially ionize) or a weak base.  Sources and related content

The given white crystalline salt dissolves in water, turning the solution blue litmus red. This indicates that the salt is acidic. When barium chloride solution is added to the solution, a white precipitate is formed. This confirms the presence of sulfate ions in the salt. Lastly, a flame test on the salt produces a persistent golden-yellow colorization, indicating the presence of sodium ions. Therefore, the salt is sodium sulfate.

Based on the given observation, sodium carbonate liberates a gas that turns lime-water milky and has no effect on acidified potassium dichromate solution. This suggests that the gas liberated is carbon dioxide, as carbon dioxide is known to turn lime-water milky. Lime water contains calcium hydroxide, and combining calcium hydroxide with carbon dioxide forms calcium carbonate as a precipitate, making the solution appear milky. Additionally, since the gas has no effect on the acidified potassium dichromate solution, it indicates that the pH of the solution is less than 7. Therefore, the correct conclusion is that both observations are correct.

The given reaction shows that when concentrated sulfuric acid (H2SO4) reacts with sodium chloride (NaCl), it liberates HCl gas as the product. This indicates that the sulfuric acid is non-volatile in nature. Volatility refers to the tendency of a substance to vaporize or evaporate. Since the reaction does not produce any volatile substances, it suggests that the sulfuric acid is non-volatile.