Copper does not react with cold water, hot water, or steam. However, iron reacts with steam. If the hot water tanks are made of steel (an alloy of iron), then iron would react vigorously with the steam formed from hot water.
\(3Fe\) + \(4H_2O\) \(→\) \(Fe_3O_4\) + \(4H_2\)
(Iron) (Steam) (Iron(II,III)oxide (Hydrogen)
That is why copper is used to make hot water tanks, and not steel.
The following distribution shows the marks of 230 students in a particular subject. If the median marks are 46, then find the values of \(x\) and \(y\).
Marks | Number of Students |
---|---|
10 -- 20 | 12 |
20 -- 30 | 30 |
30 -- 40 | \(x\) |
40 -- 50 | 65 |
50 -- 60 | \(y\) |
60 -- 70 | 25 |
70 -- 80 | 18 |