NEET Chemistry: Chemical Reactions questions with solutions

Q1. \( \mathbf{2} \boldsymbol{C a}_{3}\left(\boldsymbol{P} \boldsymbol{O}_{4}\right)_{2}+\boldsymbol{6} \boldsymbol{S} \boldsymbol{i} \boldsymbol{O}_{2}+\mathbf{1 0} \boldsymbol{C} \rightarrow \boldsymbol{P}_{4}+ \) \( \ldots . \mathrm{CaSiO}_{3}+\mathbf{1 0 C O} \) Which coefficient balances the reaction given above?

1. 2
2. 4
3. 5
4. 6 E . 8

Answer: 5

The coefficient on CaSiO3 must make calcium and silicon balance simultaneously. Since there are 6 SiO2, the product needs 6 CaSiO3, which also uses 6 Ca; the remaining calcium from 2 Ca3(PO4)2 is exactly 6, so the balance works with 6 CaSiO3 and the given other coefficients.

Q2. How many grams of magnesium oxide is formed when 4.8 gm of magnesium is combined with \( 3.2 \mathrm{gm} \) of oxygen?

1. \( 4.2 \mathrm{gm} \)
2. 3.2 gm
3. 8 gm
4. \( 16 \mathrm{gm} \)

Answer: \( 4.2 \mathrm{gm} \)

Magnesium and oxygen combine in a fixed 2:1 mole ratio to form MgO. Oxygen is the limiting reactant here, so it determines how much product can form, giving 4.2 g of magnesium oxide.