Which bonds are broken by the strong acid step?

Covalent bonds between sugar and phosphate groups in upright of DNA double strand.

Explanation:

In DNA covalent bonds of sugar and phosphate are strong bonds which can be broken by acid step. These bond are strong covalent bonds which consists of carbon atoms combined with molecule of atom. In sugar the carbon atom cannot gain or loose electron. The bond formed by carbon atom is covalent bond only.

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm