5-48. What  type  of  stain  contains  alcohol as a vehicle? 1. Spirit 2. Chemical 3. Oil 4. Water 5-49. Which  of  the  following  advantages is gained by proper surface preparation? 1. Minimum  repair  only 2. Increased  durability  only 3. Ease of repainting only 4. Each of the above 5-50. You  should  prepare  a  galvanized iron  surface  for  painting  with which of the following types of cleaners? 1. Acid wash 2. Solvent 3. Silicone 4. Latex  emulsion 5-51. Dirt and fungus are best removed from concrete and masonry by washing  with  which  of  the  following types  of  solutions? 1. Emulsion 2. Alkaline 3. Efflorescene 4. Trisodium   phosphate 5-52. During  the  process  of  removing efflorescence  from  concrete,  what should you do after scrubbing with an  acid  solution? 1. Let the solution remain on the surface about 10 min 2. Let the solution dry and then dry brush 3. Rinse  it  thoroughly  with  clear water 4. Apply a second coat of the solution, and let it remain on the surface for 30 min 5-53. What is the correct procedure for mixing muriatic acid and water? 1. Add the acid to the water 2. Add the water to the acid 3. Add 15-percent acid to 85-percent  water 4. Add half acid and half water 5-54. To repair large defects in a concrete  or  masonry  surface,  which of  the  following  grout  mixtures should you use? 1. Two parts mortar sand, 1 part portland cement, 1 part water 2. Two parts portland cement, 2 parts mortar sand, 2 parts water 3. Three parts mortar sand, 1 part portland  cement,  enough  water to  make  a  puttylike  consistency 4. Two parts mortar sand, 1 part portland  cement,  enough  water to make a soupy consistency 5-55. Before  painting,  a  plaster  patch should  set  for  what  minimum  time? 1. 1 day 2. 2 days 3. 3 days 4. Until  thoroughly  dry 5-56. When  preparing  dirty  wood  surfaces for painting, which of the following  methods  should  you follow? 1. Sweeping,  dusting,  and  washing the surface with a solvent or water and soap 2. Bleaching the surface with a solution of oxalic acid and water 3. Sanding the surface to a uniform  color 4. Pretreating  the  surface  with wood  cleaner 31