461. Carbon is present in the combined form (carbide) in case of______________________?
A. Pig iron
B. Steel
C. Ferroalloys
D. All A., B. & C.

462. The hardest material just prior to diamond in Mhos scale is_________________?
A. Topaz
B. Carborundum
C. Corundum
D. Calcite

463. Corrosion resisting properties of cast iron are significantly improved by the addition of 12 – 15% of___________________?
A. Tungsten
B. Vanadium
C. Silicon
D. All A., B. & C.

464. Which of the following is the most suitable material of construction for evaporator & its tubes for concentrating NaOH solution to 70% ?
A. Cast iron
B. Steel
C. Nickel
D. Karbate

465. Carbon content in steel is ___________________ percent?
A. 0.1-2
B. 4-6
C. 2-4
D. 0.001-0.01

466. Hastelloy comprises of____________________?
A. Copper and tin
B. Copper and nickel
C. Molybdenum and nickel
D. Lead and tin

467. Muntz metal is a/an alloys of____________________?
A. Magnesium & tin
B. Ferrous material
C. Lead & tin
D. Copper & zinc

468. Presence of even very minute amount (say 0.1%) of ______________ in copper, reduces its electrical conductivity very seriously?
A. Bismuth
B. Arsenic
C. Antimony
D. Both B. and C.

469. Cast iron detachable joint is used in __________ pipes.
A. Steel
B. Cast iron
C. Asbestos cement
D. Reinforced cement concrete

470. Which of the following metals in not used for coating of the base metal to guard it against corrosion ?
A. Lead
B. Cadmium
C. Magnesium
D. Aluminium

NOTE
IF YOU THINK ANY OF THE MCQ ABOVE IS WRONG.
PLEASE COMMENT WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION IN COMMENT BOX.
THANK YOU