Reactions of Metallic Oxides With Water: Learn in Detail

Metal hydroxides, which are naturally basic compounds, are created when metal oxides and water react. A lot of energy is released during these processes. For instance, calcium hydroxide, a basic solution, is created when calcium oxide and water react. Methanol, which is produced at a rate of about 10 million tonnes annually as a raw material for the synthesis of chemicals and for uses like fuel, is one of the common chemical platforms that are catalysed into being.

As a result, the insights gained would have an impact on all reactions, including those using water as an impurity, reactant, or product. The problem with metal oxides is that they can have “oxygen defects” where an oxygen atom is missing. Water generates two neighbouring hydroxyls, a stable molecule made up of one oxygen atom and one hydrogen atom, when it encounters one of those flaws. Continue reading to learn more reactions of metallic oxides with water.

Metal Oxides: Learn All About It

A metal cation and an oxide anion are both present in crystalline solids known as metal oxides. Normally, they interact with water to create bases or with acids to create salts. The alkali metals and alkaline earth metals can combine with oxygen to form three different types of binary oxygen compounds: oxides, which contain the ion O2, peroxides, which contain the ion O22 and contain oxygen-oxygen covalent single bonds, and superoxides, which contain the ion O2 but have one less negative charge than peroxide ions.

Alkali metals, which have an oxidation state of one, produce the compounds oxides (M2O), peroxides (M2O2), and superoxides (MO2). (The atom M stands for a metal.) Only oxides (MO) and peroxides (MO2) are formed by the alkaline earth metals (with a +2 oxidation state). By heating the matching metal nitrate with the elemental metal, one can create all of the alkali metal oxides.

The oxides’ periodic tendencies have been carefully examined. Oxides develop from ionic to covalent bonding at any given time, and their acid-base nature changes from highly basic to weakly basic to amphoteric to weakly acidic to strongly acidic. Generally speaking, basicity rises as a group descends (for example, in the alkaline earth oxides, BeO MgO CaO SrO BaO). Acidity rises when an element’s oxidation number rises.

Reaction of Metal Oxides With Water

Basic metals have oxides on them. When a metal oxide dissolves in water, a metal hydroxide is created.

Metal Oxide + Water → Metal Hydroxide

Check the example below for more clarity:

• BaO_(s) + H₂O_(l) → Ba(OH)_2(aq)
• K₂O_(s) + H₂O_(l) → 2 KOH_(aq)

Sodium’s reaction with water

When sodium metal and water interact, sodium hydroxide and hydrogen gas are produced. Water and sodium metal react so quickly that the hydrogen gas that results rapidly catches fire.

• 2Na+2H2O⟶2NaOH+H2

Metal oxides’ interaction with water

While most metal oxides are insoluble in water, alkali metal and alkaline earth metal oxides are water soluble. Metal oxides that are soluble in water react with water to produce their corresponding base. These bases, known as alkali, are extremely potent.

Example: The interaction between sodium oxide and water

Sodium hydroxide is produced when sodium oxide reacts with or dissolves in water.

• Na2O+H2O⟶2NaOH

Magnesium oxide with water’s interaction

Magnesium hydroxide results from the dissolution of magnesium oxide in water.

• Mg+2H2O⟶Mg(OH)2

These bases can be neutralised by an acid to produce salt and water, just like any other base.

Metal Oxide + Acid → Salt + Water

The examples are as follows:

• CuO_(s) + 2 HNO_3(aq) → Cu(NO₃)_2(aq) + H₂O_(l)
• Al₂O_3(s) + 6 HCl_(aq) → 2 AlCl_3(aq) + 3 H₂O_(l)

In general, an element’s oxide will be more basic the more metallic the element is. Likewise, an element’s oxide will be more acidic the more non-metallic property it possesses. Position on the periodic table can be used to establish an element’s metallic nature.

Finally, we point out that a metal and a non-metal can directly react to generate a salt.

Metal + Non-Metal → Salt

The example of this reaction is mentioned below:

• 2 Al_(s) + 3 Br_2(l) → 2 AlBr_3(s)

Reactions of Main Group Elements With Water

Two hydrogen atoms and one oxygen atom make up water. It displays polarity and can naturally exist in the states of liquid, solid, and vapour. It is referred to as the universal solvent because of its high polarity and suitability as a solvent. It is significant to note that it is involved in numerous chemical processes due to its abundance on Earth. The periodic table can be used to classify how many of these chemical reactions behave in general patterns.

Alkali Metals

The majority of alkali metals share the capacity to remove H2(g) from water as one of their common properties. Their significant negative electrode potentials serve as a representation of this. In this case, water is reduced to produce hydrogen gas and hydroxide ions while the Group 1 metal is oxidised to its metal ion. The following equation describes how an alkali metal (M) reacts generally with water (l):

2M(s)+2H2O(l)⟶2M+(aq)+2OH−(aq)+H2(g)

Alkali Metals Oxides and Water

Group 1 element oxides also combine with water to form basic solutions. When alkali metals and oxygen interact, monoxides, peroxides, or superoxide are created. These species have different reactions to water:

Monoxides: M2O(s)+2H2O(l)⟶2M+(aq)+2OH−(aq)

Peroxides: M2O2(s)+2H2O(l)⟶2M+(aq)+2OH−(aq)+H2O2(aq)

Superoxides: 2MO2(s)+2H2O(l)⟶2M+(aq)+2OH−(aq)+H2O2(aq)+O2(g)

Alkali Metal Hydrides and Water

The Group 1 element hydrides react with water to create a basic solution, just like the Group 1 oxides do. But in this instance, the metal hydroxide produces hydrogen gas. The following gives the general reaction between alkali metal hydrides and water:

MH(s)+H2O(l)⟶M+(aq)+OH−(aq)+H2(g)

Alkaline Earth Metals

Most alkaline earth metals react with water to form hydroxides as well. Even though the hydroxides of calcium, strontium, and barium are barely soluble in water, they nonetheless produce enough hydroxide ions to provide a basic environment. The following diagram illustrates the general reaction of calcium, strontium, and barium with water, where M represents either calcium, strontium, or barium:

M(s)+2H2O(l)⟶M(OH)2(aq)+H2(g)

Magnesium (Mg) and water vapour react to generate hydrogen gas and magnesium hydroxide. Only the alkaline earth metal beryllium (Be) does not react with water. As compared to the other elements in the group, it is tiny and has a high ionisation energy, which contributes to this.

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