What is the molecular formula for butane?

Butane is an alkane with a simple structure consisting of four carbon atoms. Its molecular formula is derived from the general formula for alkanes, which is (C_nH_{2n+2}), where (n) is the number of carbon atoms.

For butane, which has (n = 4), the formula calculates as follows:

• Number of carbon atoms (C) = 4
• Number of hydrogen atoms (H) = (2(4) + 2 = 10)

Thus, the molecular formula for butane is (C_4H_{10}), confirming that this is the correct choice.

The other options reflect different alkanes or hydrocarbons with varying numbers of carbon atoms which do not represent butane. For instance, (C_3H_8) is propane (with three carbon atoms), while (C_5H_{12}) indicates pentane (five carbon atoms) and (C_2H_6) is ethane (two carbon atoms). Each of these molecular formulas corresponds to a different alkane and is thus inconsistent with butane's structure.