Chemistry
State (i) composition (ii) reason for alloying (iii) one use of each of the following alloys.
(i) Brass
(ii) Bronze
(iii) Duralumin
(iv) Solder [fuse metal]
(v) Stainless steel
Answer
| Alloy | Composition | Reason for alloying | Use |
|---|---|---|---|
| 1.Brass | Cu [60 - 80%], Zn [40 - 20%] | Hard, Lustrous, easily cast, malleable, ductile | Electrical fittings, decorative articles |
| 2.Bronze | Cu [80%], Zn [1%], Sn [19%] | Hard, brittle, takes up polish | Statues, medals, coins |
| 3.Duralumin | Al [95%], Mg [0.5%], Mn [0.5%], Cu [4%] | Al - imparts lightness, Mg - imparts strength | Aircrafts, light tools, cooker |
| 4.Solder [fuse metal] | Pb [50%], Sn [50%] | Sn - lowers melting point of alloy | Electrical fuse, Soldering purposes |
| 5.Stainless steel | Fe [75%], Ni [10%], Cr [15%], C [.5%] | Ni, Cr - imparts lustre, C - imparts hardness | Utensils, cutlery, surgical instruments |
Related Questions
Give reasons for the following pertaining to Hall Herault's process.
(i) The fusion temperature of the electrolyte has to be lowered before conducting the electrolytic reduction.
(ii) The constituents of the electrolyte in addition to one part of fused alumina contains three parts of cryolite and one part of fluorspar.
(iii) A layer of powdered coke sprinkled over the electrolytic mixture, protects the carbon electrodes.
(iv) It is preferred to use a number of graphite electrodes as anode, instead of a single graphite electrode.
Define (a) alloy (b) amalgam
Loss of electrons from an element 'X' is represented by : X - 3e- ⟶ X3+ [X ⟶ X3+ + 3e-)
X is a …………… [metal/non-metal] and will form …………… [electrovalent/covalent] compounds only.
X3+ formed is a …………… [cation/anion] and element 'X' has a valency of …………… [+2/+3/-3].
If X3+ combines with oxygen the formula of the product is …………… [X2O3 / XO / X3O2]
If the above product in the …………… [solid/molten] state is electrolysed the ion X3+ will get discharged at the …………… (anode/cathode).
The ion X3+ …………… [accepts/loses] electrons and gets …………… [oxidized/reduced] to neutral …………… [ions/atoms/molecules].
The oxide of the metal which reacts with both acids and alkalis to give salt & water.
- MgO
- CuO
- Al2O3
- K2O