Assertion(A): Steel and plastic are commonly used for making safety pins. Reason(R): Steel can be molded to get sharp points and plastic is used to seal the edges. a) Both A and R are true, and R is correct explanation of the assertion, b) Both A and R are true, but R is not the correct explanation of the assertion. c) A is true, but Ris false. d) A is false, but R is true.
Answers
Answer:
The combination of more than one metal or a mixture of metal and a nonmetal in a fixed proportion are known as alloys. Certain elements are added to the mixture in a specific ratio which alters the properties of metals and strengthens the metals.
Explanation:
One of the widely used alloys in day-to-day life is steel. The base metal of steel is iron to which carbon is added in a specific ratio to improve its strength and fracture resistance. The amount of carbon in steel varies up to 2.14% of its weight.
The pure iron is ductile, soft and gets corroded when exposed to moist air but on adding carbon to it enhances the property of iron and the alloy i.e., steel formed is hard, brittle and prevents corrosions. Hence, steel has many applications in domestic as well as industrial sectors.
Some of the applications of steel are discussed below:
-Used in making tools like knives, razors, blades etc.
-Used in making the vessels.
-Used in railway tracks, wheels and gears.
Steel can also combine with polymers like plastic to give useful products. One of the common examples is safety pins. Steel and plastic are commonly used in making safety pins. Hence, option (D) is the correct answer.
Note :
It is important to note that when steel is mixed with 10.5% chromium, about 1.2% carbon and other components like nickel and nitrogen. Then the alloy formed is known as stainless steel and it is widely used in making cutlery and necessary machinery tools.