Tag: oxygen

Questions Related to oxygen

Non-metals combine with oxygen to form usually:

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. basic oxides

  2. neutral oxides

  3. acidic oxides

  4. amphoteric oxides

Show answer
Correct Option: C
Explanation:

non-metal oxides forms acid after diluting in water Eg. $\mathrm{H} _{2}C{O} _{3}, {H} _{2}S{O} _{4}$
$\therefore$   non metals combine with oxygen to from usually acidic oxcides because of its low electronegativity 

Which one of the following is an amphoteric
oxide?

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. $Na _{2}O$

  2. $SO _{2}$

  3. $B _{2}O _{3}$

  4. $\mathrm{Z}\mathrm{n}\mathrm{O}$

Show answer
Correct Option: D
Explanation:


$\mathrm Na _{2}O $ and first group oxides are basic while non-metal oxides such as $\mathrm SO _{2}$ and $B _{2}O _{3} $ are acidic.
ZnO is amphoteric because it can reacts with acid as well as base to produce salt and $\mathrm H _{2}O$.

Which of the following is not a normal oxide?

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. $\mathrm{N}\mathrm{a} _{2}\mathrm{O}$

  2. $\mathrm{Al} _{2}\mathrm{O} _{3}$

  3. $\mathrm{K}\mathrm{O} _{2}$

  4. $\ \mathrm{M}\mathrm{g}\mathrm{O}$

Show answer
Correct Option: C
Explanation:

$KO _2 \rightarrow K^+ O _2^-$
Hence, $KO _2$ is a super oxide with $O _2^-$ ion.
$Na _2O, Al _2O _3, M _gO$ are normal oxides with $O^{2-}$ ion.

Which of the following elements forms amphoteric oxides?

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. Beryllium

  2. Aluminium

  3. Zinc

  4. All

Show answer
Correct Option: D
Explanation:

An amphoteric species is a molecule or ion that can react as an acid as well as base. The word amphoteric means both. Many metals such as copper, zinc, tin, lead, aluminium and beryllium form amphoteric oxides or hydroxides.

Metal oxide which show basic as well as acidic behaviour are known as:

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. neutral oxide

  2. amphoteric oxide

  3. metalloid oxide

  4. none of the above

Show answer
Correct Option: B
Explanation:

Metal oxides which shows basic as well as acidic behaviour as known as amphoteric oxides. Thus aluminium metal and zinc metal form amphoteric oxides.

Which of the following oxide is thermally least stable?

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. $CaO$

  2. $Al _2O _3$

  3. $Fe _2O _3$

  4. $Ag _2O$

Show answer
Correct Option: A
Explanation:

The melting points and thermal stability of the oxides are determined by the nature of the distribution of valent electrons from the components over localized and nonlocalized ones and by the probability of the formation of stable electron configurations of transition metal and oxygen atoms. The drop in statistical weight of stable configurations and increase in proportion of nonlocalized electrons results in a drop in melting point and thermal stability of the oxides.

Calcium oxide is thermally least stable as it reacts exothermically with water producing hydroxide.
$CaO +H _2O \rightleftharpoons Ca(OH) _2$

Match the following, regarding nature of the oxides.

Column -I Column-II
a. $N _2O$ (i) Basic
b. BaO (ii) Amphoteric
c. $As _2O _3$ (iii) Acidic
d. $Cl _2O _7$ (iv) Neutral
chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. a(ii), b(i), c(iii), d(iv)

  2. a(iv), b(i), c(iii), d(ii)

  3. a(iv), b(i), c(ii), d(iii)

  4. a(ii), b(i), c(iv), d(iii)

Show answer
Correct Option: C
Explanation:

(A) $N _2O\longrightarrow$ (iv) Neutral as it neither shows properties of a base nor acid.

(B) $BaO\longrightarrow$ (i) Basic; Metallic oxides are basic oxides.
(C) $As _2O _3\longrightarrow$ (ii) Amphoteric as it can act both as a base and an acid.
(D) $Cl _2O _7\longrightarrow$ (iii) Acidic as non-metallic oxides are acidic in nature.

Which of the following oxide is most acidic ?

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. $P _2O _5$

  2. $N _2O _5$

  3. $Sb _2O _5$

  4. $As _2O _6$

Show answer
Correct Option: B
Explanation:

$N _2O _5$ is the most acidic as it is having $+5$ oxidation state with highest electronegativity of $N$.

A light metal M is a good conductor of electricity. It forms a layer when exposed to air, which is an amphoteric oxide of the formula $M _2O _3$. Identify M.

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. Ca

  2. Al

  3. Mg

  4. Ba

Show answer
Correct Option: B
Explanation:

Here, only $Al$ forms amphoteric oxide of formula $Al _2O _3$.

It forms protective layer of $Al _2O _3$ when exposed to air.

$Na _2O$, $MgO$, $Al _2O _3$ and $SiO _2$ have heat of formation equal to $-416,\ -602,\ -1676$ and $-911$ $ kJ mol^{-1}$ respectively. The most stable oxide is:

chemistry chemistry of non-metals oxides of elements simple oxides oxygen

  1. $Na _2O$

  2. $MgO$

  3. $Al _2O _3$

  4. $SiO _2$

Show answer
Correct Option: B
Explanation:
$(B)$ A smaller higher charged ion will be closer to the oxide ions $(O^{2-})$, which means the thermal stability of $MgO$ is more or it takes more energy to break the crystal structure of $MgO$