Oxides of elements - class-XII

As metallic character decreases as we move across the period then basicity of oxides increases.

Dioxygen reacts with metals and is paramagnetic. It combines with other elements to form oxides where the reaction is highly exothermic.

$ZnO$ is an amphoteric oxide. It reacts with both acid and base to produce respective salts. 

here,${ CrO } _{ 3 }$ are acidic oxides

In chromium oxides, the basic character decreases as the oxidation state of chromium increases. CrO has chromium in the +2 state, making it the most basic.

HgO (mercuric oxide) is thermally unstable and can be easily decomposed into mercury metal and oxygen by heating, making it the easiest to reduce.

ZnO reacts with HCl to form ZnCl2 and water, and with NaOH to form Na2ZnO2 (sodium zincate) and water. This dual behavior confirms that ZnO is amphoteric.

As metal oxides are basic and Tl2O3 makes salt and water after reacting with acid. 

An oxide which forms salts when it reacts with both acids and alkali is knwn as amphoteric oxides. $e.g.$ $Al _2O _3$.

Al2O3 (aluminum oxide) is a classic example of an amphoteric oxide, as it reacts with both strong acids and strong bases.

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 

$\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 $\mathrm H _{2}O$.

$KO _2 \rightarrow K^+ O _2^-$
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.

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

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.

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

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

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

The correct answer is $(B),SnO _2$ 

The binary compound of elements with oxygen is called oxides. Here oxygen is anionic part. So suffix is 'ide'.

Amphoteric oxides show acidic and basic nature. They react with both acids and bases. 

Group element having high electronegativity will be most acidic.

$Mg$ forms oxide as well as nitride.

Given that in${ XO } _{ 2 },50%$% of $O _2$ is present

Because it absorbs $CO _2$ and increases $O _2$ concentration according to the following reaction

$4K{ O } _{ 2 }+2{ CO } _{ 2 }\rightarrow 2{ K } _{ 2 }{ CO } _{ 3 }+3{ O } _{ 2 }$

The $Pb{ O } _{ 2 }$ behaves as acidic and basic property so it is called as amphoteric.

For the second oxide M2O3, 70% is metal, so 30% is oxygen. The ratio of moles M:O is (70/M) : (30/16) = 2:3. Solving gives M = 56 (Iron). For the first oxide (72.4% metal), ratio is (72.4/56) : (27.6/16) = 1.29 : 1.725 = 3:4. Thus, M3O4.

As the electronegativity value of the element increases. the acidic character of the oxide also increases.

Here among $N,P,SI$ and $As$ the most electronegative is $N$.

Thus the most acidic is $N _2O _5$.

$Cl _2O _7$ is most acidic because on reacting with water , it gives  most strongest acid than the other three i.e., $HClO _4$ .

In HCO2- (formate ion), the C-O bond length is an average due to resonance, but it is generally shorter than a single bond and longer than a double bond. Comparing it to CO3(2-), the bond lengths are similar due to resonance, making statement C incorrect.

The scum is formed when soap is used in hard water and hard water consists of carbonate. For this process $Oxides$ ions responsible for scum formation.

As the oxidation state of a metal increases, its metallic character decreases and the covalent character of its oxide increases, leading to more acidic behavior. In CrO3, chromium is in the +6 oxidation state, making it acidic rather than basic, and thus it is the least basic among the choices.

Mass ratio A:O = 7:3. Moles ratio = (7/AtomicWeightA) : (3/16). If A=56 (Iron), ratio = (7/56) : (3/16) = 0.125 : 0.1875 = 2:3. Formula is A2O3.

Using mass conservation, moles of Ti in 1.6 g of TiO2 can be calculated. By finding the mass of oxygen removed during reduction by hydrogen, we determine the empirical formula of the resulting titanium oxide to be Ti2O3.

$Na _2O$ , MgO are basic oxides.

Lithium shows tendency to form peroxide (Li2O2) unlike other alkali metals. This is due to its small size and high charge density. Other alkali metals primarily form normal oxides.

Carbon monoxide (CO) does not react with acids or bases to form salts under normal conditions, classifying it as a neutral oxide. In contrast, SnO2 and ZnO are amphoteric, and SO2 is acidic.

Oxides can be called as binary compounds formed by the reaction of oxygen with other elements.  Oxides are classified as acidic, basic, amphoteric or neutral.  An oxide is a compound that contains at least one oxygen atom and one other element in its chemical formula.  Oxide is a dianion of oxygen.  Examples of oxides are CaO, BaO, ZnO etc.

Acidic strength increases with oxidation state: P2O5 (P in +5), N2O5 (N in +5), SO3 (S in +6). Higher oxidation states attract electron density more strongly, making oxides more acidic. Order: P2O5 < N2O5 < SO3.

Oxyacid, any oxygen-containing acid. Most covalent nonmetallic oxides react with water to form acidic oxides; that is, they react with water to form oxyacids that yield hydronium ions (H3O+) in solution. There are some exceptions, such as carbon dioxide, CO, nitrous oxide, N2O, and nitric oxide, NO.

Basic oxides are typically formed by metals, especially alkali and alkaline earth metals. Among the choices, magnesium oxide (MgO) is a strongly basic metal oxide, whereas P2O5 and B2O3 are acidic, and SnO is amphoteric.

A normal oxide contains the O(2-) ion. SiO2 is a covalent network solid that behaves as a normal acidic oxide. KO2 and CsO2 are superoxides, and BaO2 is a peroxide.

$PbO _2$ is amphoteric so it can act as acid as well as base. Also it is strong oxidising agent.

$Al _2O _3$ is amphoteric oxide, apart from this all other are neutral oxides.

In $ {PbO} _{2}, $ Its $ Pb^{+4}$ & $ 2O^{-2} $

A metal oxide is acidic when $\sqrt{\varphi}, >, 3.2$

$CaO$, $CO _2$ and $SiO _2$ when dissolved in water gives base ,hence they are basic oxides.

 $CO$ is a neutral oxide insoluble in water, but behaves as amphoteric compound. 

(A) BeO is amphoteric in nature. It reacts with acids as well as alkalies.  Oxides of other s block metal elements are basic in nature. They react only with acids. hence, the option A is correct.

Only true peroxides which have -O-O- bond give hydrogen peroxide with dilute acids.
$PbO _2$ does not give hydrogen peroxide with dilute acids. So it is not a true peroxide.

Acidic oxides are the oxides which reacts with water to form an acid. Acidic are non- metallic oxides. Some of the examples are ${ SO } _{ 3 }$ forms sulphuric acid and ${ CO } _{ 2 }$ forms carbonic acid. 

Amphoteric compound or ion is a molecule that cn act as both acid as well as base.

$\displaystyle HSO^- _4$ can be classified as amphoteric. It can donate a proton and act as an acid. At the same time, it can accept a proton and act as a base.
$\displaystyle HSO^- _4 \rightarrow H^+ + SO _4^{2-}$
$\displaystyle HSO^- _4 + H^+ \rightarrow H _2SO _4$

Amphoteric specie is $\displaystyle HSO _4^-$.
It reacts with acid as well as base.
$\displaystyle HSO _4^- + H^+ \rightarrow H _2SO _4$
$\displaystyle HSO _4^-+ OH^- \rightarrow SO _4^{2-} + H _2O$

Sodium sulphite is formed by passing sulphur dioxide gas through the solution of sodium hydroxide because sulphur dioxide is an acidic oxide.

Neutral oxides are those that do not react with either acids or bases. NO (Nitric oxide) is a well-known neutral oxide.

Amphoteric species can act as both acids and bases. H2O, H2PO3-, and HPO4(2-) can all donate or accept protons depending on the reaction environment.

• Neutral oxides show neither basic nor acidic properties and hence do not form salts when reacted with acids or bases.
  
• Carbon and oxygen together have a total of 10 valence electrons in carbon monoxide. To satisfy the octet rule for the carbon, the two atoms form a triple bond, with six shared electrons in three bonding molecular orbitals, rather than the usual double bond found in organic carbonyl compounds. Since four of the shared electrons come from the oxygen atom and only two from carbon, one bonding orbital is occupied by two electrons from oxygen, forming a dative or dipolar bond. This causes a $C\leftarrow O$ polarization of the molecule, with a small negative charge on carbon and a small positive charge on oxygen. Overall the molecule is neutral.
  
• Hence option A is correct answer.

ZnO is amphoteric because it can act with acid as well as base.
$ZnO + NaOH \rightarrow Na _2ZnO _2$
$ZnO+HCl \rightarrow ZnCl _2$

Most stable oxide is that whose  formation const, $K _f$ is largest 

$SnO _2$ shows both acidic and basic properties $\therefore$ it is amphoteric in nature.

Mn forms acidic oxide $MN _2O _7$ and it is a transtition metal.

Metal being electropositive in nature form basic oxide .non metals being electronegative in nature from acidic oxides .

HSO4- and H2PO2- are amphoteric. H2O is amphoteric. Since all options listed are amphoteric, the correct choice is that none of them are 'not amphoteric'.

The superoxide ion is O2(-). RbO2 is rubidium superoxide, which contains the O2(-) ion. BaO2 is a peroxide (O2(2-)), and NaO2 is a superoxide, but RbO2 is the classic example often cited in this context.

Matching the oxide types: N2O is a neutral oxide (iv), BaO is a strong basic oxide (i), As2O3 is an amphoteric/weakly acidic oxide (commonly classed as amphoteric or intermediate, matching ii here), and Cl2O7 is a strong acidic oxide (iii). This correctly aligns with option C.

 Amphoteric oxide is one that reacts with both acids and bases to form salt and water. Thus,  SnO and SnO2 react with both HCl (an acid) and NaOH (base) to give salt and water.

$ Cr(OH) _3$ reacts with bases (hydroxide ions) to give $ [Cr(OH) _6]^{3-}$. It also reacts with acids (hydrogen ions) to give $ [Cr(H _2O) _6]^{3+}$ 

An amphoteric solution is a substance that can chemically react with either acid or base. For example, when $HSO _4^-$ reacts with water it will make both hydroxide and hydronium ions. Amphoteric oxides are metallic oxides, which show both basic as well as acidic properties. When they react with an acid, they produce salt and water, showing basic properties. While reacting with alkalies they form salt and water showing acidic properties.  A common example of an amphoteric oxide is aluminium oxide, Zinc Oxide, SnO, PbO.

$Zn(OH) _2$   amphoteric in nature
$HClO _4$      strong acid
$NaOH$         strong base

Basic oxides will be formed by metals. Potassium is a metal and it forms basic oxides.

ZnO is an amphoteric oxide, meaning it reacts with both acids (HCl) and bases (NaOH) to form salts and water.

'$Al$' and '$Zn$' reacts with both acids and bases. So, these are amphoteric in nature. So, oxides of these elements are amphoteric oxides. 

Aluminium reacts with acids and bases. So, it is amphoteric in nature. The oxide of an amphoteric element is called amphoteric oxide. So, $Al _{2}O _{3} $ is an amphoteric oxide.

Sodium is a metal and metal oxides are basic in nature. So, $Na _{2} O$ is a basic oxide. It is not neutral oxide.

${ N } _{ 2 }O,CO,{ H } _{ 2 }O$ these are some samples of neutral oxides.

Neutral oxide are those which do not react with acids as well as bases such as $NO,{ N } _{ 2 }O,CO,{ O } _{ 2 }{ F } _{ 2 }$.

$B _2O _3$ is more acidic than $CO _2$ and $N _2O _5$ because oxides of elements of 13th group of modern periodic table is more acidic than than 14th and 15th group elements.