Answer is option B
because CO2,SO2 and NO2 contains both sigma and pi bonds but H2O contains sigma bonds.

Introduction:
In this question, we need to identify the molecule that does not contain a pi bond. A pi bond is a type of covalent bond that is formed by the sideways overlap of two atomic orbitals. It is characterized by the sharing of electron density above and below the internuclear axis.

Explanation:
Let's analyze each option to determine if it contains a pi bond or not.

A. CO2:
CO2, also known as carbon dioxide, consists of one carbon atom bonded to two oxygen atoms. In the Lewis structure of CO2, the carbon atom forms two double bonds with the oxygen atoms. Each double bond consists of one sigma bond and one pi bond. Therefore, CO2 contains two pi bonds.

B. H2O:
H2O, also known as water, consists of two hydrogen atoms bonded to one oxygen atom. In the Lewis structure of H2O, the oxygen atom forms two sigma bonds with the hydrogen atoms. However, there are no pi bonds present in H2O. The oxygen atom has two lone pairs of electrons, which occupy the p orbitals and do not participate in pi bonding.

C. SO2:
SO2, also known as sulfur dioxide, consists of one sulfur atom bonded to two oxygen atoms. In the Lewis structure of SO2, the sulfur atom forms one double bond and one single bond with the oxygen atoms. The double bond in SO2 consists of one sigma bond and one pi bond. Therefore, SO2 contains one pi bond.

D. NO2:
NO2, also known as nitrogen dioxide, consists of one nitrogen atom bonded to two oxygen atoms. In the Lewis structure of NO2, the nitrogen atom forms one double bond and one single bond with the oxygen atoms. Similar to SO2, the double bond in NO2 consists of one sigma bond and one pi bond. Therefore, NO2 contains one pi bond.

Conclusion:
Among the given options, the molecule that contains no pi bond is H2O (B). It consists of only sigma bonds and does not have any pi bonds. CO2, SO2, and NO2 all contain at least one pi bond in their Lewis structures.