Is there any legal evidence that the boundaries of the face for Wudu’ (ablution) are from the hairline to the chin lengthwise, and from ear to ear widthwise, or is it an ijtihad (independent reasoning) by scholars?

The boundaries of the face, agreed upon by scholars, linguistically and Islamically, extend from the hairline to the end of the jawbones lengthwise, and from ear to ear widthwise. They have based their reasoning on the Almighty's saying: ("wash your faces"), and on the fact that the face, in language, is that by which confrontation occurs.