Question

К реакциям замещения относится:а) горение фосфораб) реакция между гидроксидом лития и соляной кислотойв) реакция между калием и водойг) разложение гидроксида алюминия при нагревании

Answer 1

Верный ответ будет под буквой в)
2K + H20 = K20 + H2 (зам.)

Answer 2

Reactions of Substitution

The reaction of substitution involves the replacement of one atom or group of atoms with another atom or group of atoms in a chemical compound. It is a common type of chemical reaction that occurs in various contexts. Let's analyze the given options to determine which one represents a reaction of substitution.

a) Burning of phosphorus: The burning of phosphorus is not an example of a substitution reaction. It is a combustion reaction where phosphorus reacts with oxygen to form phosphorus pentoxide. This reaction involves the combination of a substance with oxygen, not the substitution of atoms or groups.

b) Reaction between lithium hydroxide and hydrochloric acid: The reaction between lithium hydroxide (LiOH) and hydrochloric acid (HCl) is a neutralization reaction, not a substitution reaction. In this reaction, lithium hydroxide reacts with hydrochloric acid to form lithium chloride and water. The hydroxide ion (OH-) from lithium hydroxide combines with the hydrogen ion (H+) from hydrochloric acid to form water, while the lithium ion (Li+) combines with the chloride ion (Cl-) to form lithium chloride.

c) Reaction between potassium and water: The reaction between potassium (K) and water (H2O) is an example of a displacement reaction. In this reaction, potassium displaces hydrogen from water, resulting in the formation of potassium hydroxide (KOH) and the release of hydrogen gas (H2). This is a classic example of a metal displacement reaction.

d) Decomposition of aluminum hydroxide upon heating: The decomposition of aluminum hydroxide (Al(OH)3) upon heating is not a substitution reaction. It is a decomposition reaction where aluminum hydroxide breaks down into aluminum oxide (Al2O3) and water vapor (H2O) when heated. This reaction involves the breakdown of a compound into simpler substances, not the substitution of atoms or groups.

Based on the analysis above, the correct answer is c) the reaction between potassium and water. This reaction represents a substitution reaction where potassium displaces hydrogen from water to form potassium hydroxide and release hydrogen gas.

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