Hi, the question has some missing part. The complete question should be " If the 
of 
is 3.74 and the pH of an 
solution is 3.89, it means that -
(a) ![[HCHO_{2}]=[NaCHO_{2}]](https://tex.z-dn.net/?f=%5BHCHO_%7B2%7D%5D%3D%5BNaCHO_%7B2%7D%5D)
(b) ![[HCHO_{2}]> [NaCHO_{2}]](https://tex.z-dn.net/?f=%5BHCHO_%7B2%7D%5D%3E%20%5BNaCHO_%7B2%7D%5D)
(c) ![[HCHO_{2}]< [NaCHO_{2}]](https://tex.z-dn.net/?f=%5BHCHO_%7B2%7D%5D%3C%20%20%5BNaCHO_%7B2%7D%5D)
Which of the options are true?"
Answer: Option (c) is true.
Explanation:
is an weak acid-conjugate base buffer. Hence, in accordance with Henderson-Hasselbalch equation-
![pH=pK_{a}(HCHO_{2})+log(\frac{[CHO_{2}^{-}]}{[HCHO_{2}]})](https://tex.z-dn.net/?f=pH%3DpK_%7Ba%7D%28HCHO_%7B2%7D%29%2Blog%28%5Cfrac%7B%5BCHO_%7B2%7D%5E%7B-%7D%5D%7D%7B%5BHCHO_%7B2%7D%5D%7D%29)
Here, pH = 3.89, of = 3.74
So, ![3.89=3.74+log(\frac{[CHO_{2}^{-}]}{[HCHO_{2}]})](https://tex.z-dn.net/?f=3.89%3D3.74%2Blog%28%5Cfrac%7B%5BCHO_%7B2%7D%5E%7B-%7D%5D%7D%7B%5BHCHO_%7B2%7D%5D%7D%29)
or, ![\frac{[CHO_{2}^{-}]}{[HCHO_{2}]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BCHO_%7B2%7D%5E%7B-%7D%5D%7D%7B%5BHCHO_%7B2%7D%5D%7D)
= 1.41 (>1)
So, ![[CHO_{2}^{-}]> [HCHO_{2}]](https://tex.z-dn.net/?f=%5BCHO_%7B2%7D%5E%7B-%7D%5D%3E%20%5BHCHO_%7B2%7D%5D)
or, ![[NaCHO_{2}]> [HCHO_{2}]](https://tex.z-dn.net/?f=%5BNaCHO_%7B2%7D%5D%3E%20%5BHCHO_%7B2%7D%5D)
Hence, option (c) is correct.
Molarity = (Mass/ molar mass) x (1/ volume of solution in Litres)
Mass = Molarity x molar mass x volume of solution in Litres
Molarity of Tris = 100 mM = 0.1 M
volume of Tris sol. = 100 mL = 0.1 L
molar mass of Tris = 121.1 g/mol
Hence,
mass of Tris = Molarity of Tris x molar mass ofTris x volume of Tris solution
= 0.1 M x 121.1 g/mol x 0.1 L
= 1.211 g
mass of Tris = 1.211 g
The energy of the wave does not move through anything
The height it's falling, wind pressure, force, the weight of the object etc
