Chemistry MCQs for NEET — Practice Questions with Answers

Oxygen typically has an oxidation state of -2 in most of its compounds. However, it can also have an oxidation state of -1 in peroxides (such as H2O2). The other options provided are not common oxidation states for oxygen.

Stock notation is used for naming compounds of metals that have more than one possible oxidation state. For example, FeCl2 is named iron(II) chloride, and FeCl3 is named iron(III) chloride.

The molecular formula of sodium chromate (VI) is $Na_2CrO_4$. Sodium chromate is an inorganic compound with the formula $Na_2CrO_4$. It is a yellow crystalline solid that is often used in industrial applications.

The name of $K_2Cr_2O_7$ according to the stock notation nomenclature method is Potassium dichromate (VI). The (VI) indicates the oxidation state of chromium, which is +6 in this compound.

The name of $TiO_2$ according to the stock notation nomenclature method is Titanium (IV) oxide. The (IV) indicates the oxidation state of titanium, which is +4 in this compound.

In $ Fe_3O_4 $, iron exhibits two different oxidation states: +2 and +3. There are two Fe atoms with +3 oxidation state and one Fe atom with +2 oxidation state. This is why the ratio of atoms with oxidation states +2 and +3 in $ Fe_3O_4 $ is 1:2.

The correct proportion of FeO and $ Fe_2O_3 $ in $ Fe_3O_4 $ is 1:1, not 1:2. Hence, the statement that the proportion of FeO and $ Fe_2O_3 $ is 1:2 is incorrect.

Barium peroxide (BaO2) contains the peroxide ion (O2^2-). The structure of BaO2 consists of Ba^2+ cations and O2^2- anions. This can be remembered by noting that BaO2 is commonly used as a source of peroxide in inorganic chemistry.

Barium peroxide (BaO2) contains the peroxide ion (O2^2-), not superoxide (O2^-). The confusion may arise because O2^- (superoxide) and O2^2- (peroxide) are closely related, but BaO2 specifically has the peroxide ion (O2^2-).