The following obligations cannot be specifically enforced: (1) An obligation to render personal service; (2) An obligation to employ another in personal service; (3) An agreement to submit a controversy to arbitration except as authorized in the Uniform Arbitration Act; (4) An agreement to perform an act which the party has not power lawfully to perform when required to do so; (5) An agreement to procure the act or consent of the spouse of the contracting party, or of any other third person; (6) An agreement, the terms of which are not sufficiently certain, to make the precise act which is to be done clearly ascertainable. Source: CivC 1877, § 1999; CL 1887, § 4632; RCivC 1903, § 2344; RC 1919, § 2015; SDC 1939 & Supp 1960, § 37.4602; SL 1971, ch 157 , § 26; SL 1979, ch 149 , § 11.