Introduction to organic chemistry

Which is the correct general formula for the specified non-cyclic, open-chain homologous series?

saturated diols — $CnH2nO2\text{C}_n\text{H}_{2n}\text{O}_2$

alkadienes (with two $C=C\text{C}=\text{C}$ double bonds) — $CnH2n−4\text{C}_n\text{H}_{2n-4}$

saturated dicarboxylic acids — $CnH2n−2O4\text{C}_n\text{H}_{2n-2}\text{O}_4$

saturated dihaloalkanes — $CnH2n−2X2\text{C}_n\text{H}_{2n-2}\text{X}_2$ (where $X\text{X}$ is a halogen)

Which is the correct general formula for the specified non-cyclic, open-chain homologous series?

saturated diols — $CnH2nO2\text{C}_n\text{H}_{2n}\text{O}_2$

alkadienes (with two $C=C\text{C}=\text{C}$ double bonds) — $CnH2n−4\text{C}_n\text{H}_{2n-4}$

saturated dicarboxylic acids — $CnH2n−2O4\text{C}_n\text{H}_{2n-2}\text{O}_4$

saturated dihaloalkanes — $CnH2n−2X2\text{C}_n\text{H}_{2n-2}\text{X}_2$ (where $X\text{X}$ is a halogen)

Introduction to organic chemistry Questions