It is a great interest of research to explore the superconductivity in 111-family superconductor with strong spin orbit-interaction. In this proposal we wish to investigate role of spin orbit coupling in the newly discovered ScRuSi (ortho), ScRhP and ScIrP. ScRuSi (ortho), ScRhP and ScIrP exhibits superconductivity between 2 and 3.4 K. Using Ginzburg-Landau formula upper critical field is estimated to be HC2 = 0.87 T, 0.5 T and 5 T for ScRuSi (ortho), ScRhP and ScIrP respectively. Specific heat jump was found to be 1.55 and 1.23 for ScRuSi and ScIrP respectively. In this proposal we want to investigate microscopic superconducting properties of ScRuSi (ortho), ScRhP and ScIrP using transverse field, zero field MuSR measurements.