Question

Trimethylphosphine, P(CH₃)₃, can act as a ligand by donating the lone pair of electrons on the phosphorus atom. If trimethylphosphine is added to a solution of nickel(II) chloride in acetone, a blue compound that has a molecular mass of approximately 270 g and contains 21.5% Ni, 26.0% Cl, and 52.5% P(CH₃)₃ can be isolated. This blue compound does not have any isomeric forms. What are the geometry and molecular formula of the blue compound?

a) Octahedral, [NiCl₂(P(CH₃)₃)₄]
b) Tetrahedral, [NiCl₂(P(CH₃)₃)₄]
c) Square Planar, [NiCl₂(P(CH₃)₃)₄]
d) Trigonal Bipyramidal, [NiCl₃(P(CH₃)₃)₂]

Answer 1

The blue compound formed from the reaction of trimethylphosphine and nickel(II) chloride has a B) tetrahedral geometry, and its molecular formula is [NiCl2(P(CH3)3)2], which confirms option b).

Step-by-step explanation:

The blue compound formed when trimethylphosphine reacts with nickel(II) chloride can be determined through stoichiometry and knowledge of coordination chemistry.

Since we are provided with the percentage composition and the molecular mass, we can calculate the empirical formula of the compound.

Knowing that there are no isomers, which suggests a symmetry in the molecule, and based on common coordination geometries of nickel(II), which typically forms tetrahedral or square planar complexes, we can deduce the molecular formula and geometry.

Based on the calculations, the compound's molecular formula matches to b) Tetrahedral, [NiCl2(P(CH3)3)2] with a geometry that is non-complex and lacks isomers, fitting well with the molecular mass of approximately 270 g/mol.