Ans. is 'd' i.e. Sodium hypochloriteCommon Disinfectants for Hospital UseGroupExamples and UsageAdvantages and DisadvantagesPHENOLICSClear-soluble phenolic compounds, white fluids; 1.5% solutions; leave in contact for 1 hour.Good general purpose disinfectants, not readily inactivated by organic matter, active against wide range of organisms (including mycobacteria) but not sporicidal.HALOGENSHypochlorites (chloramine) eg "Milton", "Domestic", bleaches. Strong (2% Cl) to weak (0.02% Cl) concentrations used according to degree of blood contamination; leave in contact for 30 minutes.Cheap, effective, act by release of free chlorine, active against viruses and therefore recommended for disinfection of equipment soiled with blood (because of hepatitis risk), but rapidly inactivated by organic material and corrosive to metals.ALCOHOLSEthyl alcohol (ethanol), isopropyl alcohol (isopropanol).Good choice for skin disinfection and for clean surfaces, sometimes used in combination with iodine or chlorhexidine, water must be present for bacterial killing (i.e. 70% ethanol best), isopropanol preferred for skin and articles in contact with patient.ALDEHYDESGlutaraldehyde ("Wavicide", "Aidel"); 1% solution, leave in contact for 30 minutes.Kills vegetative organisms including mycobacteria slowly but effectively. More active, less toxic than formaldehyde, sporicidal (within 6 hours when fresh), irritant, used in alkaline solution which is stable 1-2 weeks, expensive, limited use e.g. disinfection of endoscopes.