Question

please answer i will brainliest​

Answer 1

Explanation:

please mark as brainliest please

Answer 2

Question :-

The COD value of a water sample is 40 ppm calculate the amount of acidified K$_2$Cr$_2$O$_7$ required to oxidise the organic matter present in 500ml of the water sample

AnSwer :-

COD value is 40ppm. It means 10⁶g of water sample require 40 g of oxygen to oxidise the organic matter in it.

$\sf500ml \: water \longrightarrow \dfrac{40 \times 500}{ {10}^{6} } = 2 \times {10}^{ - 2} g \: of \: O _{2}$

500ml water sample requires 2 × 10$^{-2}$ g of O$_2$, to oxidise the organic matter present in it.

$\sf2 \times {10}^{ - 2} g \: of \: O_2 = \dfrac{49 \times 2 \times {10}^{ - 2} }{8} g \: of \: K_2 Cr_2 O_7$

Amount of K$_2$Cr$_2$O$_7$ required to oxidise the organic matter present in the water sample is 0.1225g.