Goldsmiths uses aqua regia, which is prepared by mixing

What is the composition of aqua regia?

A

1:3 of HCl and HNO3

B

1:3 of HNO3 and HCl

C

1:3 of HCl and H2SO4

D

1:3 of H2SO4 and HCl

What is the composition of aqua-regia that corrodes noble metals such as platinum, gold?

A

3 parts of nitric acid and 1 part of hydrochloric acid

B

3 parts of hydrochloric acid and 1 part of nitric acid

C

1 part of hydrofluoric acid and 3 part of hydrochloric acid

D

3 parts of hydrofluoric acid and 1 part of hydrochloric acid

Aqua regia is a 1 : 3 mixture, by volume, of

A

Conc. nitric acid and conc. hydrochloric acid

B

Conc. hydrochloric acid and conc. nitric acid

C

Conc. nitric acid and conc. sulphuric acid

D

Conc. sulphuric acid and conc. nitric acid

Aqua regia is an acidic, corrosive and oxidative mixture consisting of . . . . . . . . volume/volumes of concentrated hydrochloric acid and one volume of concentrated nitric acid, often used to dissolve gold and platinum.

A

Two

B

Three

C

One

D

Four

A mixture of concentrated nitric acid and concentrated hydrochloric acid in the ratio of . . . . . . . . is called Aqua-Regia.

A

3 : 1

B

1 : 2

C

2 : 3

D

1 : 3

The mixing vat in a factory receives liquid ingredients through six separate value--- labeled R.S.T.U,Y and Z -- each of which has exactly two settings: open and closed.The mixing vat operator must ensure that each valve is set open or closed according to the following conditions: If T is open, both S and Z must be closed, R and Z cannot both be closed at the same time; If Y is closed, Z must also be closed;S and U cannot both be open at the same time. Which of the following, if given to the mixing vat operator as an instruction, would not determine the setting of any other valve ?

A

S must be open

B

T must be open

C

U must be open

Mixing Index is a ratio of the standard deviation of various products during mixing to that at zero mixing.

A

True

B

False

A batch of 20% of Acetic acid is prepared by mixing the Acetic acid of two containers A and B. A (400 kg) contains 80% of Acetic acidand B contains 15% of Acetic acid. 9. How much kg of acid is prepared?

A

5700

B

7600

C

8000

D

9800

Delonix regia কোনটির বৈজ্ঞানিক নাম-

A

কৃষ্ণচূড়া

B

অশোক

C

অরহর

D

ছোলা

Delonix regia কোনটির বৈজ্ঞানিক নাম?

A

কৃষ্ণচূড়া

B

অশোক

C

অড়হড়

D

কালকাসুন্দা