AP EAPCET 04-Jul-2022 Shift 2 Paper

(a) Mg+NO3−→Mg2++NH3
The complete balanced equation of the given . reaction is
4‌Mg+NO3−+9H⊕→4Mg2++NH3+3H2O
Given, conc. of NO3−=0.1M
Volume of NO3−=100‌mL
We know that,
Molarity =‌

‌ Number of moles ‌

‌ Volume of solution (in L) ‌

‌‌ Hence, number of moles ‌=‌ molarity ‌×‌ volume of solution (in L) ‌
‌‌ So, number of moles ‌=0.1×100×10−3‌=10m‌mol‌=10−2‌mol
From above Eq.,
1 mole NO3−reacts with 4 moles Mg.
So, IO−2 mole NO3−reacts with 4×10−2 moles Mg.
Now, to calculate the mass of Mg required, use the formula,
Number of moles =‌

‌ Given mass ‌

‌ Molar mass ‌

Molar mass of Mg=24gmol−1
On substituting the value,‌‌4×10−2=‌

‌ Mass of ‌Mg

24

We will get,
‌‌ Mass of ‌Mg=24×4×10−2
‌‌ Mass of ‌Mg=0.96g