Test: Study of Acids, Bases and Salts - Class 10 MCQ

Efflorescence refers to the process where hydrated salts lose their water of crystallization when exposed to air, leading to a powdery substance. This phenomenon can be observed in substances like gypsum, which can lose water and form a dry powder.

A strong base is one that undergoes nearly complete ionization in water, producing a high concentration of hydroxide ions (OH⁻). Examples include sodium hydroxide (NaOH) and potassium hydroxide (KOH), which are commonly used in various industrial applications.

The pH scale measures the concentration of hydrogen ions (H⁺) in a solution. A lower pH indicates higher acidity, while a higher pH indicates alkalinity. The scale typically ranges from 0 to 14.

Concentrated acids are characterized by having a high percentage of acid relative to water, meaning they contain very little water or none at all. This makes them highly reactive and potentially dangerous, requiring careful handling.

Normal salts are formed by the complete replacement of the replaceable hydrogen ions of an acid molecule by a basic radical. An example is sodium chloride (NaCl), created from the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH).

A monobasic acid is defined as an acid that, upon ionization in water, yields one hydronium ion (H₃O⁺) for each molecule of the acid. A common example is hydrochloric acid (HCl), which dissociates to produce one H₃O⁺ ion.

The reaction that qualifies as a neutralization reaction involves an acid and a base reacting to form a salt and water. In this case:

• HCl (hydrochloric acid) is an acid.
• NaOH (sodium hydroxide) is a base.
• The products are NaCl (sodium chloride) and H₂O (water).

This matches the definition of a neutralization reaction, where the acid and base neutralise each other.

Strong acids exhibit a high concentration of hydronium ions (H₃O⁺) in solution due to their complete ionization. This property makes them effective electrolytes and also contributes to their corrosive nature.

Bases are known for their bitter taste and the ability to turn red litmus paper blue. This is a common indicator reaction that helps to distinguish bases from acids, which turn blue litmus red.

Acetic acid (CH₃COOH) is classified as a weak acid because it only partially ionizes in aqueous solution, producing fewer hydronium ions compared to strong acids like hydrochloric acid (HCl) or sulfuric acid (H₂SO₄).

A strong acid is one that completely ionizes in aqueous solution, resulting in a high concentration of hydronium ions (H₃O⁺). Examples include hydrochloric acid (HCl) and sulfuric acid (H₂SO₄), which dissociate fully, making the solution capable of conducting electricity well.

The reaction between an acid and a base that produces a salt and water is known as a neutralization reaction. This is a fundamental type of chemical reaction that is important in both laboratory and industrial processes.

Organic acids contain carbon and hydrogen, and they are primarily obtained from plant sources. Common examples include acetic acid (found in vinegar) and citric acid (found in citrus fruits). Unlike inorganic acids, which do not contain carbon, organic acids often play essential roles in biological processes.

All alkalis are bases that produce hydroxide ions (OH⁻) when dissolved in water. This property distinguishes them from other types of bases and allows them to neutralize acids effectively.

H₂SO₄ (sulfuric acid) is an example of an oxyacid, which contains oxygen, hydrogen, and a non-metallic element (sulfur). Oxyacids generally have higher oxidation states and are important in various chemical processes.

The reaction of an acid with a carbonate to yield salt, water, and carbon dioxide is classified as a neutralization reaction. This process is evident in the reaction between hydrochloric acid and calcium carbonate, where CO₂ is released as a gas.

Indicators are substances that change color in response to changes in pH, providing a visual cue during acid-base reactions. For example, phenolphthalein turns pink in basic solutions and colorless in acidic solutions, making it useful for determining the endpoint of titrations.

Aluminum hydroxide (Al(OH)₃) is a triacidic base because it can dissociate to produce three hydroxide ions (OH⁻) per molecule. This classification helps in understanding its reactivity and applications in various chemical reactions.

Dibasic acids are characterized by their ability to produce two hydronium ions (H₃O⁺) per molecule when dissolved in water. An example is sulfuric acid (H₂SO₄), which can release two protons in solution.

Double salts are formed by the combination of two simple salts that crystallize together and dissolve in water. A well-known example is potash alum, which consists of potassium sulfate and aluminum sulfate. These salts can exhibit unique properties different from their constituent salts.