Aluminium reacts with aqueoussodium hydroxide (NaOH) and producesodium aluminate (NaAlO2) & hydrogengas as products. NaAlO2 is soluble in water. Aluminium reacts with bases becauseAluminium is anamphoteric element.

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## Al(s) + NaOH(aq) + H2O(l) → NaAlO2(aq) +H2(g)

For this reaction, water is contributed as a reagent. This is a redox reaction. Aluminium is oxidized lớn its+3oxidation state & oxidation number of hydrogen atom is increased from +1 to 0.

Sometimes this reaction is expressed as below.

## Balanced equations of aluminium & sodium hydroxide reaction

Because this reaction is a redox reaction, we can follow steps of redox reactions balancing. Balancedequations for both types are mentioned below.

### Al + NaOH + H2O → NaAlO2 + H2

Write down oxidation numbers of each element in the left side và right side.Identify which elements are oxidized and reduced. Aluminum is oxidized và hydrogen atoms in the waterand NaOH are oxidized.balance number of atoms of oxidized và reduced. There are one Al in both left side & right side.Therefore Al atoms should not be equalized.Also, there are, three hydrogen atoms in the left side & two in right side. Now, we need khổng lồ balancenumber of hydrogen atoms in right side và left side.Balancing hydrogen atoms in right side & left sideMake two water molecules in the left side. Then total hydrogen atoms in the left side will become five.It is not yet balanced hydrogen atoms in right side and left side.Make three hydrogen molecules in the right side. Now, there are six hydrogen atoms in the right side.Still, hydrogen atoms are not balanced.Make two NaOH in the left side. Then total hydrogen atoms in the left side will become six now.Finally, number of hydrogen atoms in both sides are equal.oxidation number differences in oxidation & reductionAluminium is oxidized from 0 to +3. Therefore, oxidation number difference of oxidation is 3.There are six hydrogen atoms with +1 oxidation state. In the right side, there are six hydrogen atomswith 0 oxidation state. Therefore oxidation number difference of reduction is 6.Exchange oxidation number differences between oxidized & reduced atoms

When you exchange oxidation number differences between oxidized and reduced atoms, take the simplest ratio ofoxidation number differences.In this reaction, oxidation number differences of oxidation và reduction is 3 to 6 (3:6). Therefore, simplestratio is 1 to lớn 2 (1:2)Exchange ratios as following.Questions asked by students.

### As aluminium, what are the other metals which can react with aqueous NaOH?

Beryllium, zinc, lead & tin react with aqueous NaOH.

### Is the reaction of aluminium and sodium hydroxide corrosive?

Aluminium is protected due lớn its oxide layer exists on its surface. But, due khổng lồ amphoteric characteristics of aluminium, it tends lớn react with sodium hydroxide. Aluminium oxide layer dissolves in aqueous sodium hydroxide solution.

### Why is NaOH not kept in Aluminium containers?

Aluminium reacts with NaOH và emit hydrogen gas. Therefore reaction happens continuosly until one reactant is finished. Therefore, NaOH is not kept in Aluminium containers

### Cannot prepare aluminium hydroxide from aluminium and sodium hydroxide?

Aluminium hydroxide is soluble in aqueous sodium hydroxide solution. When, we add excess sodium hydroxide to lớn aluminium,sodium aluminate is given.But, adding dilute HCl acid will neutralize OH- ions and will give Al(OH)3white precipitate.Aluminium hydroxide is ainsoluble hydroxide in water.

### What are the similar reactions to lớn aluminium and sodium hydroxide we can see in chemistry?

As aluminium, other amphoteric metals such as beryllium, zinc, lead and tin react with aqueous bases such as sodium hydroxide.

Questions

### As aluminium và sodium hydroxide will give sodium aluminate, what are the other ways of preparing sodium aluminate>

Industrially, sodium aluminate is produced by dissolution of aluminium hydroxide in a caustic soda (NaOH) solution.

### Will give a precipitate when aluminium reacts with sodium hydroxide solution?

Sodium aluminate is a soluble salt in water.

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### Uses of Al + NaOH reaction?

We know, hydrogen gas is produced in this reaction. Hydrogen gas can be used as a fuel. Usually children use this reaction khổng lồ send balloons by burning produced hydrogen gas. This is a risk because balloons can be fallen down to lớn roofs of houses và may lead to lớn fires in those houses.