Answer:
Option D is the correct answer
Explanation:
There are three hydrogen bonds formed between Guanine and Cytosine base.
The first hydrogen bond is formed between the oxygen atom on Carbon-6 (C-6) of guanine, and one of the hydrogen atoms attached to the Nitrogen atom (i.e the one of the hydrogen atoms in the amino group) on the Carbon-4 (C-4)of the cytosine base.
The second hydrogen bond is formed between the hydrogen atom on Nitrogen-1 (N-1) of the guanine base and Nitrogen-3 (N-3) of the cytosine base.
The third hydrogen bond exist between one of the hydrogen atoms in the amino group attached to the second Carbon (C-2) of the guanine base, and the oxygen atom attached to the second Carbon (C-2) of the cytosine base.
Answer:
pH is the number given to a substance of how powerful it is before 7 or beyond 7.
the solution is an acid.
Explanation:
Pls mark BRAINLIEST
NaHCO3 is the required substance often used in antacid and is used in Soda Acid Fire Extinguisher.
Answer:
In the option(A) moles of HCl left are 0.100 moles which is wrong, making the option incorrect.
Explanation:

Moles of HCl = n
Molarity of HCl = 1.0M
Volume of HCl solution = 30.0 mL = 0.030 L (1 mL = 0.001L)


Moles of Fe = 
According to recation , 1mol of Fe reacts with 2 mol HCl. Then 0.01 mole of Fe will recat with :
of HCl
This means that HCl uis in excess , hence excessive reagent.
Moles of HCl left unreacted :
= 0.030 mol - 0.020 mol = 0.010 mol
But in the option moles of HCl left are 0.100 moles which is wrong, making the option incorrect.