General Knowledge - General Science - Discussion
Discussion Forum : General Science - Elements and Metals (Q.No. 1)
1.
Brass gets discoloured in air because of the presence of which of the following gases in air?
Discussion:
254 comments Page 21 of 26.
Gauri said:
1 decade ago
As brass is an alloy of copper and zinc, the copper when kept free to air reacts with hydrogen sulphide and so the alloy is discoloured.
Nepal ranjan said:
1 decade ago
Primary ingredients of brass are cu& zn. When brass exposed in the air then H2S reacts. Cu reacts with Sulphide forms cu2s which is colored black and zn reacts with hydrogen forms zinc hydroxide which color is faint red. That's why it gets discolored exposed in air.
Jyothi said:
1 decade ago
Becuase of oxidation any metal is discoloured in the process of oxidation.
Yochana said:
1 decade ago
How can you say that H2S is present in the atmosphere?
Aoke Soe Paing said:
1 decade ago
The question is "which of the following gases". So the answer may be two or more gases. I think that as both of oxygen and H2S are in the air.
Rahulramesh said:
1 decade ago
Any metal is discoloured in the process of oxidisation.
G urudatt said:
1 decade ago
Bars is made of cu and zn. Brass is a elements of transitee.
Raju Mandal said:
1 decade ago
Brass is alloy of Cu and Zn. When it reacts with hydrogen sulfide(H2S).
It forms Cu2S(which is black in color) and ZnH2(which turns greyish on exposure to air at room temp). Hence answer is hydrogen sulfide
It forms Cu2S(which is black in color) and ZnH2(which turns greyish on exposure to air at room temp). Hence answer is hydrogen sulfide
ANTRIKSH said:
1 decade ago
I think brass is the combination of copper also and it is reacts sulphor fast other than all these also zinc present in brass reacts with hydrogen but no any mixer reacts directly with the air whenever moisture is not present.
Ramesh Naik Dhanavath said:
1 decade ago
Primary ingredients of of brass are Copper&zinc. When brass exposed to air the hydrogen sulphide in the atmosphere is react with copper&zinc.
Copper reacts with sulphide ion and forms cupric sulphide which is black in color where as zinc reacts with hydrogen and forms zinc hydroxide which is faint red in color. Hence brass gets discolored when it exposed to air.
Copper reacts with sulphide ion and forms cupric sulphide which is black in color where as zinc reacts with hydrogen and forms zinc hydroxide which is faint red in color. Hence brass gets discolored when it exposed to air.
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