Answer : A - carboxyl group.
The carbon in the carboxyl group is bonded to a hydroxyl group and also it is double bonded to an oxygen group.
The carboxyl group when it is dissolved in a solution donates it's hydrogen ion(H+ ion). When it is dissolved in water, the carboxyl group loses its H+ ion to form negatively charged ion.
RCOOH + H2O⇄RCOO- + H3O+
Thus the carboxyl group act as an acid when dissolved in water.
The ionic compound of FePO4 is the iron III phosphate. Or you can call it ferric phosphate or ferric orthophosphate.
Just for general informations, It's normally used in steel and metal manufacturing processes, in organic farming, and many other uses.
Hope this Helps :)
Answer: Would be D. Fe and S have an ionic bond, while S and O have covalent.
Hope that helps.
Answer:
FAS concentration = 1.61*10^-4M
Explanation:
Beer Lambert's law relates the absorbance (A) of a substance to its concentration (c) as:

where ε = molar absorption coefficient
l = path length
A plot of 'A' vs 'c' gives a straight line with slope = εl
In addition absorbance (A) is related to % Transmittance (%T) as:
A = 2-log%T----(2)
For the FAS solution, the corresponding calibration fit is given as:
y = 3678(x) + 0.056
This implies that the slope = εl = 3678
It is given that %T = 25.6%

Based on equation(1):

It is a ,d and c just make sure tho