A. Hydrochloric acid
B. Nitric acid
C. Sulphuric acid
D. Phosphoric acid
Related Mcqs:
- Gypsum bonded investment should not be heated over______________?
A. 700°C
B. 1,300°C
C. 1,063°C
D. 900°C - Quartz is added to gypsum bonded investment to______________?
A. Increase the strength
B. Counter balance contraction of gypsum during heating
C. aid in hygroscopic expansion
D. Increase the shelf life of investment - A thinner mix of a gypsum bonded investment will_______________?
A. Produce a smoother casting
B. Decrease setting expansion
C. Increase setting expansion
D. Increase thermal expansion - The product, which is obtained by calcining gypsum under steam pressure at 120-130°C or by dehydrating gypsum in the presence of sodium succinate is_______________?
A. Alpha – hemihydrates
B. Beta – hemihydrates
C. Calcium sulphate dihydrate
D. Orthorhombic anhydrate - Binder in phosphate bonded investment is______________?
A. Magnesium oxide & Phosphate
B. Magnesium oxide & Phosphoric acid
C. Magnesium oxide & Monoammonium phosphate
D. Magnesium oxide & Ortho Phosphoric acid - Binder used in Gypsum investment is_________________?
A. Silica
B. Quartz
C. Cristobolite
D. Calcium sulphate monohydrate - The strength of a gypsum investment is dependent on_______________?
A. Carbon content
B. Silica content
C. Gypsum
D. Copper - Accelerators and retarders are used with gypsum products mainly to control_______________?
A. Setting time
B. Setting expansion
C. Hardness of the set product
D. None of the above - The β (Beta) hemihydrate of gypsum requires more water to float its powder particles because______________?
A. They are more regular in shape and dense
B. They are more regular in shape and highly porous
C. They are more irregular in shape and porous
D. They are more dense and prismatic in shape - Gypsum is used for________________?
A. Impressions
B. Casts
C. Die
D. Casts and Dies
