Which is chirla CH₃CH₂OHCH₂CH₃ orCH₃CHOHCH₃

A chiral organic compound is the one that contains a carbon atom attached to four different atoms or group of atoms. Among the given compounds, CH₃CH(OH)CH₂CH₃ is a chiral compound as the second carbon atom is attached to four different atoms or group of atoms. This is evident from the given structure of the compound,

While as the second compund is not chiral or achiral, as the second carbon atom is attached to two methyl groups (as shown in the figure below),