What is the optical activity of the product formed when propanone is refluxed with HCN with KCN dissolved in ethanol and why?

The product formed (hydroxybutanitrile) is optically inactive because the nitrile nucleophile can attack the propane at its carbonyl bond which is trigonal planar about it. There is an equal chance of it attacking above or below the bond which means that the product is a racemic mixture (equal amounts of both enantiomers) who's optical activity cancel each other out, making the product optically inactive