add

Question 1

10% sulfuric acid and potassium dichromate.

Answer 1

For cast iron and cast steel –

Question 2

solution no. 1
(hydrochloric acid is 80 ml,
water is 60 ml,
cupric chloride is 2.9 grams
and alcohol are 50 ml)

Solution no. 2 (15% nitric acid)

Answer 2

For wrought iron and forged iron –

Question 3

– glycerin is 30 ml, nitric acid is 10 ml, and hydrofluoric acid is 20 ml.

Answer 3

For aluminum

Question 4

– 3 parts glacial acetic acid and one-part water.

Answer 4

For lead

Question 5

– dilute sulfuric acid or 10% hydrochloric acid in alcohol.

Answer 5

For stainless steel

Question 6

ferric chloride – 19 grams, hydrochloric acid – 6 ml, and water – 100 ml.

Answer 6

For copper, brass, silver and other copper alloy –

Question 7

– 10% hydrochloric acid.

Answer 7

For tin

Question 8

– 10% sodium hydroxide.

Answer 8

For zinc

Question 9

concentrated nitric acid.

Answer 9

For silver

Question 10

aqua regia (3 parts hydrochloric acid and one-part nitric acid)

Answer 10

For gold and platinum

Question 11

– subject to a jet of steam.

Answer 11

For wood