Heat require to boil 15.6 g iron from 122 C0to 355 C0 whereas,

Where, m is mass of iron
s is specific heat of iron
d T is change in temperature in celcius

If
1 cal = 4.2 J
Then,

Thus 0.389 k cal of enrgy is required by a 15.6 g Fe to reach to 355 C^0
Obliviously not all rocks have holes in them
It is called vesicular texture These refers to viscles holes pores or cavities within the igneous rock.the vesicles are the result of gas expansion(bubbles).which often occur during volcanic eruptions .
For the basic solution:
11.2 = -log[H+]
[H+] = 6.31 x 10⁻¹²
For the acidic solution:
2.4 = -log[H+]
[H+] = 3.98 x 10⁻³
The difference:
3.98 x 10⁻³ - 6.31 x 10⁻¹²
≈ 4.0 x 10⁻³
The answer is B
<span> a) AgNO3 (aq) + KCl (aq) --> AgCl (s) + KNO3 (aq) this is balanced chemical equation
</span><span>AgCl is the precipitate so we shall not split it
</span><span>Ag+(aq) + NO3 -(aq) + K+ (aq) + Cl-(aq) --> AgCl (s) + K+(aq) + NO3-(aq)
</span><span>Ag+ (aq) + Cl- (aq) ---> AgCl (s) after removing ions</span>