Aluminum dissolves in mineral acids and aqueous alkalis and thus shows amphoteric character. A piece

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p-Block Elements - I

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Aluminum dissolves in mineral acids and aqueous alkalis and thus shows amphoteric character. A piece of aluminum foil is treated with dilute hydrochloric acid or dilute sodium hydroxide solution in a test tube and on bringing a burning match stick near the mouth of the test tube, a pop sound indicates the evolution of hydrogen gas. The same activity when performed with concentrated nitric acid, reaction doesn't proceed. Explain the reason.

Option A

Option B

Option C

Option D

Solution

Aluminum is amphoteric in nature, it reacts with acid and base to give salt and $\mathrm{H}_{2}$ gas. It burns with pop sound.

$2 \mathrm{Al}+6 \mathrm{HCl} \rightarrow 2 \mathrm{AlCl}_{3}+3 \mathrm{H}_{2}$

$2 \mathrm{Al}+\mathrm{NaOH}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{NaAlO}_{2}+3 \mathrm{H}_{2}$

When $\mathrm{Al}$ reacts with conc. $\mathrm{HNO}_{3}$, a thin layer of $\mathrm{Al}_{2} \mathrm{O}_{3}$ on the surface of $\mathrm{Al}$ metal which protect further reaction. This layer is called protective layer.

$2 \mathrm{Al}+6 \mathrm{HNO}_{3} \rightarrow \mathrm{Al}_{2} \mathrm{O}_{3}+6 \mathrm{NO}_{2}+3 \mathrm{H}_{2} \mathrm{O}$

Standard 11

Chemistry

The correct statement$(s)$ for orthoboric acid is/are

$(A)$ It behaves as a weak acid in water due to self ionization.

$(B)$ Acidity of its aqueous solution increases upon addition of ethylene glycol.

$(C)$ It has a three dimensional structure due to hydrogen bonding.

$(D)$ It is weak electrolyte in water.

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(IIT-2014)

Assertion : Both $Be$ and $Al$ can form complexes such as $BeF_4^{2-}$ and $AlF_6^{3-}$ respectively, $BeF_6^{3-}$ is not formed.
Reason : In case of $Be$, no vacant $d-$ orbitals are present in its outermost shell.

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(AIIMS-2015)

Which of the following is known as inorganic benzene

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The species, having bond angles of $120^o $ is

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(NEET-2017)

When metal $X$ is treated with sodium hydroxide, a white precipitate $(A)$ is obtained, which is soluble in excess of $NaOH$ to give soluble complex $(B)$. Compound $(A)$ is soluble in dilute $HCl$ to form compound $(C)$. The compound $(A)$ when heated strongly gives $(D)$, which is used to extract metal. Identify $(X), (A), (B), (C)$ and $(D)$. Write suitable equations to support their identities.

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Solution

Similar Questions

Assertion : Both $Be$ and $Al$ can form complexes such as $BeF_4^{2-}$ and $AlF_6^{3-}$ respectively, $BeF_6^{3-}$ is not formed. Reason : In case of $Be$, no vacant $d-$ orbitals are present in its outermost shell.

Which of the following is known as inorganic benzene

The species, having bond angles of $120^o $ is

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Assertion : Both $Be$ and $Al$ can form complexes such as $BeF_4^{2-}$ and $AlF_6^{3-}$ respectively, $BeF_6^{3-}$ is not formed.
Reason : In case of $Be$, no vacant $d-$ orbitals are present in its outermost shell.