Question

Among (a)$N{a_2}O$, (b)$MgO$, (c)$A{l_2}{O_3}$, (d)${P_2}{O_5}$, (e)$C{l_2}{O_7}$, the most basic, most acidic and amphoteric oxide can be respectively:

Answer 1

Hint: The oxides of metals, nonmetals and metalloids have different nature of acidity or basicity. The oxides of metals are generally basic, oxides of non-metals are acidic and the metalloids are amphoteric.

Complete step by step answer:
Elements in the periodic table have capacity to combine with oxygen and form their respective oxides. The elements on the extreme left side of the periodic table i.e. alkali metals and alkaline earth metals combine to oxygen to form metal oxides. The metal oxides are generally basic in nature. The reason for their basicity is that they combine with water to form hydroxide
$\left( {{\text{ - OH}}} \right)$ ions and they combine with acids to form salts. In the given question, $\left( a \right)N{a_2}O,\left( b \right) MgO$ are metal oxides so they are the most basic oxides.
Similarly the elements in the extreme right side of the table, the non-metals i.e. the halogens of 17th group also combine with oxygen to form non-metal oxides. They form generally most acidic oxides. The reason for their acidic nature is, they form mineral acids upon reaction with water and also give salts with bases. From the given examples, $\left( d \right){P_2}{O_5},\left( e \right)C{l_2}{O_7}$ are non-metal oxides hence they are considered the most acidic oxides.
In the same manner, the option $\left( c \right)A{l_2}{O_3}$ is an example of amphoteric oxide. Because aluminum trioxide possesses both acidic and basic characteristics and it has the ability to react with both acids and bases.

Note: Sodium and magnesium belong to s-block elements and they are metals. So, metal oxides are basic for their ability to form acids with water. Phosphorus and chlorine belong to the p-block and have non-metallic nature. Aluminum though it is a metal, its oxide acts as an amphoteric oxide.