How can solid lead iodide be separated from solution?

A. Because it does not react with water

B. Because it does not contain hydrogen ions (H+)

C. Because it contains hydrogen ions but not chloride ions (Cl-)

D. Because hydrogen is bonded to chlorine in dry HCl and not dissociated

A) Because it does not react with water: While dry hydrogen chloride gas does not react with water, the absence of this reaction does not inherently determine its acidity. Acidity is determined by the presence of hydrogen ions in solution.

B) Because it does not contain hydrogen ions (H+): Dry hydrogen chloride gas does not contain free hydrogen ions, which are characteristic of acidic solutions. However, the absence of hydrogen ions alone does not explain why dry hydrogen chloride gas is not acidic.

C) Because it contains hydrogen ions but not chloride ions (Cl-): Dry hydrogen chloride gas does not contain free chloride ions, but the presence of hydrogen ions is crucial for acidity. However, the absence of chloride ions alone does not fully explain why dry hydrogen chloride gas is not acidic.

D) Because hydrogen is bonded to chlorine in dry HCl and not dissociated (Correct Answer): Dry hydrogen chloride gas does not dissociate into hydrogen ions (H+) and chloride ions (Cl-) because there is no water present to facilitate dissociation. Therefore, it does not exhibit acidic properties in the absence of dissociation.

A. Iron

B. Iron sulfide

C. Copper chloride

D. Sulfur

A. Iron (Correct Answer): Iron can react with hydrochloric acid to produce hydrogen gas according to the following reaction:

2HCl + Fe => FeCl2 + H2

So, adding iron to dilute hydrochloric acid would produce hydrogen gas.

B. Iron sulfide: Iron sulfide may react with hydrochloric acid, but it does not directly produce hydrogen gas. The reaction would likely produce hydrogen sulfide gas instead.

C. Copper chloride: Copper chloride does not react with hydrochloric acid to produce hydrogen gas. The reaction between copper chloride and hydrochloric acid would likely produce copper chloride and hydrogen chloride gas.

D. Sulfur: Sulfur does not react with hydrochloric acid to produce hydrogen gas. The reaction between sulfur and hydrochloric acid would likely produce hydrogen sulfide gas.

A. Yellow, green, and blue colors.

B. Green, blue, and purple colors.

C. White, grey, and black colors.

D. Yellow, orange, and red colors

A. Yellow, green, and blue colors: This sequence of colors does not represent the typical color changes observed in universal indicator when exposed to acidic solutions. Universal indicator typically changes from green/blue in neutral solutions to yellow/orange/red in acidic solutions.

B. Green, blue, and purple colors: Purple is not typically observed in the color changes of universal indicator in acidic solutions. Universal indicator usually transitions from green/blue in neutral solutions to yellow/orange/red in acidic solutions.

C. White, grey, and black colors: These colors are not typically observed in the color changes of universal indicator. Universal indicator undergoes a series of color changes from green/blue to yellow/orange/red in acidic solutions.

D. Yellow, orange, and red colors. (Correct Answer): Universal indicator typically changes from green/blue in neutral solutions to yellow/orange/red in acidic solutions. This sequence of colors represents the typical color changes observed in universal indicator when exposed to acidic solutions.

A. Because it reacts vigorously with acids

B. Because it forms a basic solution when dissolved in water

C. Because in solution it fully dissociates into K+ and OH-

D. Because it forms insoluble precipitates with metal cations

A) Because it reacts vigorously with acids: While KOH does react with acids to form salts and water, the strength of an alkali is not solely determined by its reactivity with acids.

B) Because it forms a basic solution when dissolved in water: This statement is true, but it does not fully explain why KOH is considered a strong alkali. Many compounds can form basic solutions when dissolved in water.

C) Because in solution it fully dissociates into K+ and OH- (Correct Answer): KOH is considered a strong alkali because it fully dissociates in aqueous solution into potassium ions (K+) and hydroxide ions (OH-). This dissociation leads to a high concentration of hydroxide ions in solution, making it strongly alkaline.

D) Because it forms insoluble precipitates with metal cations: This statement describes the formation of insoluble hydroxide precipitates when alkali solutions are added to solutions of metal salts. However, it does not fully explain why KOH itself is considered a strong alkali.

A. Filtration

B. Distillation

C. Evaporation

D. Decantation

A) Filtration (Correct Answer): Filtration is a commonly used method to separate solid particles, such as unreacted copper oxide, from a liquid solution. The solution containing the dissolved copper sulfate can pass through the filter paper, while the solid copper oxide particles are retained on the filter.

B) Distillation: Distillation is a process used to separate components of a mixture based on differences in their boiling points. It is not typically used to separate solid particles from a liquid solution.

C) Evaporation: Evaporation involves heating the solution to allow the solvent (water) to vaporize, leaving behind the solute (copper sulfate) as solid crystals. While evaporation can concentrate the solution, it does not effectively remove solid particles like unreacted copper oxide.

D) Decantation: Decantation involves pouring off the liquid portion of a mixture, leaving the solid behind. While it can be used to separate solid and liquid phases, it may not effectively separate fine solid particles like unreacted copper oxide from the solution. Filtration would be a more suitable method for this purpose.

A. Salt and water

B. Carbon dioxide and water

C. Oxygen gas and water

D. Hydrogen gas and water

A) Salt and water (Correct Answer): When an acid reacts with a metal hydroxide, a salt and water are typically produced. The metal in the metal hydroxide combines with the acid to form a salt, and water is produced as a byproduct of the reaction.

B) Carbon dioxide and water: This reaction occurs when an acid reacts with a metal carbonate, not a metal hydroxide. When carbonates react with acids, carbon dioxide gas is produced along with water and a salt.

C) Oxygen gas and water: This reaction is not typical when an acid reacts with a metal hydroxide. Metal hydroxides generally do not produce oxygen gas when reacting with acids.

D) Hydrogen gas and water: This reaction occurs when an acid reacts with a metal, not a metal hydroxide. When metals react with acids, hydrogen gas is typically produced along with water and a salt.

A. To provide energy for photosynthesis

B. To build cellulose in cell walls

C. To build amino acids and proteins

D. To regulate water uptake

A) To provide energy for photosynthesis: While nitrogen is essential for various metabolic processes in plants, it is not directly involved in providing energy for photosynthesis. Instead, plants use sunlight to convert carbon dioxide and water into glucose during photosynthesis.

B) To build cellulose in cell walls: Nitrogen is not directly involved in the synthesis of cellulose, which is primarily composed of glucose units. Cellulose synthesis mainly relies on carbon and hydrogen, which are obtained from carbon dioxide and water during photosynthesis.

C) To build amino acids and proteins: Plants use nitrogen from fertilizers to synthesize amino acids and proteins. Nitrogen is a crucial component of amino acids, the building blocks of proteins, which are essential for plant growth, development, and various physiological processes.

D) To regulate water uptake (Correct Answer): Nitrogen plays a role in regulating various physiological processes in plants, including water uptake. It affects the osmotic potential of plant cells and helps regulate the movement of water and nutrients within the plant.

A. Salt and water

B. Carbon dioxide and water

C. Oxygen gas and water

D. Salt and hydrogen gas

A) Salt and water: This reaction occurs when an acid reacts with a metal hydroxide or a metal oxide, not with a metal carbonate or metal hydrogen carbonate.

B) Carbon dioxide and water (Correct Answer): When an acid reacts with a metal carbonate or metal hydrogen carbonate, carbon dioxide gas is produced along with water and a salt. The carbonates decompose into carbon dioxide gas, water, and a salt when reacting with acids.

C) Oxygen gas and water: This reaction is not typical when an acid reacts with a metal carbonate or metal hydrogen carbonate. Metal carbonates and metal hydrogen carbonates generally do not produce oxygen gas when reacting with acids.

D) Salt and hydrogen gas: This reaction occurs when an acid reacts with a metal, not with a metal carbonate or metal hydrogen carbonate. When metals react with acids, hydrogen gas is typically produced along with a salt.

A. Metal oxides are bases and forms alkalis in water.

B. Non-metal oxides form acids in water.

C. Solutions of non-metal oxides change red litmus blue.

D. Metal oxides color universal indicator blue and non-metal oxides color it red.

A. Metal oxides are bases and form alkalis in water: This statement is generally true. Metal oxides typically react with water to form basic solutions (alkalis). Therefore, this statement is true.

B. Non-metal oxides form acids in water: This statement is generally true. Non-metal oxides typically react with water to form acidic solutions. Therefore, this statement is true.

C. Solutions of non-metal oxides change red litmus blue: This statement is not true. Non-metal oxides typically form acidic solutions in water, which would not change red litmus paper to blue. Instead, they would typically turn blue litmus paper red.

D. Metal oxides color universal indicator blue and non-metal oxides color it red: This statement is generally true. Metal oxides tend to produce basic solutions, which turn universal indicator blue. Non-metal oxides tend to produce acidic solutions, which turn universal indicator red. Therefore, this statement is true.

A. Water

B. Ammonia and Water

C. Ammonium salt

D. Hydrogen gas

A) Water: Water is not typically produced when an acid reacts with ammonia. Water may be present in the reaction mixture, but it is not a direct product of the reaction between the acid and ammonia.

B) Ammonium chloride: Water and ammonia  are not typically produced when an acid reacts with ammonia. 

C) Ammonium salt (Correct Answer): When an acid reacts with ammonia, an ammonium salt is typically formed. The specific ammonium salt produced depends on the acid used in the reaction.

D) Hydrogen gas: Hydrogen gas is not typically produced when an acid reacts with ammonia. The reaction between an acid and ammonia does not involve the liberation of hydrogen gas.