HT Histotechnician

Answer: D - 10% solution
The ideal preparation or concentration of formaldehyde used in the laboratory is that of a 5% and a 10% solution. Therefore, it must be diluted by 1:10 parts with distilled water for a 10% solution, and 1:20 parts with distilled water for a 5% solution. A 10% formaldehyde solution preserves a wide range of tissues and has the advantage of being a versatile fixative.