Hydrogen single-replacement reactions

The reaction of lithium and water is a single-replacement reaction. Lithium replaces a hydrogen in water, and the products of the reaction are aqueous lithium hydroxide and hydrogen gas. Lithium hydroxide exists as lithium and hydroxide ions in solution. 

Single-replacement reactions Now that you ve seen how atoms and molecules rearrange in synthesis and combustion reactions, look closely at the reaction between lithium and water that is shown in Figure 10-8. The expanded view of the reaction at the molecular level shows that a lithium atom replaces one of the hydrogen atoms in a water molecule. The following chemical equation describes this activity. 

The reaction between lithium and water is one type of single-replacement reaction in which a metal replaces a hydrogen in a water molecule. Another type of single-replacement reaction occurs when one metal replaces another metal in a compound dissolved in water. For example. Figure 10-9 shows a single-replacement reaction occurring when a spiral of pure copper wire is placed in aqueous silver nitrate. The shiny crystals that are accumulating on the copper wire are the silver atoms that the copper atoms replaced. 

In single-replacement reactions, a metal may replace hydrogen in water, a metal may replace another metal in a compound dissolved in water, and a non-metal may replace another nonmetal in a compound. 

Single-replacement reaction magnesium replaces hydrogen in nitric acid, and hydrogen gas is formed. 

Single-replacement reactions The reaction between lithium and water is shown in Figure 9.12. The following chemical equation shows that a lithium atom replaces one of the hydrogen atoms in a water molecule. 

Figure 8.15 Reaction of sodium with water. A single-replacement reaction occurs when sodium, an element, reacts with water, a compound. The metal sodium appears to replace hydrogen in water, 2 Na + 2 HOH (A + BX) 2 NaOH + Hj (AX + B). The... 

Acids react with some metals to form hydrogen gas in what is termed a single replacement reaction. In a single replacement reaction, one element is released from a formula and the remaining element combines with the reacting element. 

In the single replacement reaction shown in Figure 8.5, zinc replaces hydrogen in hydrochloric add, HCl aq). 

Acids react with certain metals to produce hydrogen gas (H2) and a salt. Active metals include potassium, sodium, calcium, magnesium, aluminum, zinc, iron, and tin. In these single replacement reactions, the metal ion replaces the hydrogen in the acid. 

The reactions of hydrogen and oxygen to form water and carbon and oxygen to yield carbon dioxide are examples of combination reactions. A combination or synthesis reaction results when two or more substances unite to form a compound. Many other types of reactions exist. Three other common types of reactions are decomposition, single replacement, and double replacement. 

In the cathodic reduction of substrates with appropriate leaving groups X, these groups can be replaced by hydrogen in a reaction which is termed cathodic cleavage . A mechanism is assumed involving the reduction of the substrate to a radical anion that dissociates into a radical and X, sometimes both reactions occur in a single step (dissociative electron transfer) [153]. The radical is further reduced to an anion that is subsequently protonated (Eq. 19). 

Hydrogen ions of acids and hydrogen gas occupy a unique position in the activity series (Section 9.5). All other members of this series are metals and metal ions that engage in single-replacement-type redox reactions. The reaction of the hydrogen ion appears in the net ionic equation for the reaction of calcium with hydrobromic acid ... 

Single Displacement Reaction in this single-displacement reaction, the hydrogen in hydrochloric acid, HCI, is replaced by magnesium, Mg. 

One example of a single displacement reaction is when magnesinm replaces hydrogen in water to make magnesium hydroxide and hydrogen gas ... 

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