MCQs

Explanation
Vitamin K is essential for the synthesis of clotting factors in the blood. Its deficiency leads to prolonged bleeding or poor blood clotting.

Explanation
In the modern periodic table, there are 7 periods (horizontal rows) and 18 groups (vertical columns).

Explanation
NO₂ (Nitrogen dioxide) is a covalent compound , made of nonmetals (nitrogen and oxygen) sharing electrons. The others like (NH₄)₂CO₃, HNO₃, and AgCl involve ionic bonding either fully or in part (e.g., NH₄⁺ acts ionically).

Explanation
Dative bond : This is a type of covalent bond where one atom donates both electrons to the bond, forming a coordinate covalent bond. In this case,  NH₃ (ammonia)  (with a lone pair of electrons) acts as the electron donor , and  BF₃ (boron trifluoride)  (electron deficient) acts as the electron acceptor .

Explanation
John Dalton proposed the Atomic Theory in the early 1800s , stating that all elements are made of indivisible atoms. He described atoms as indestructible and identical for each element, laying the foundation of modern chemistry .

Explanation
A reaction in which heat is absorbed is called an endothermic reaction. These reactions lower the temperature of their surrounding area, thereby creating a cooling effect.

Explanation
Given y = 3: Step 1: Calculate y³. y³ = 3³ = 27 Step 2: Calculate y³ - y. y³ - y = 27 - 3 = 24 Step 3: Calculate y³(y³ - y). y³(y³ - y) = 27 × 24 = 648

Explanation
When a projectile moves upward , gravity acts downward. This opposes the vertical motion , so the vertical component of velocity decreases until it becomes zero at the highest point.

Explanation
20 men can construct a building in 40 days. Total work = 20 men × 40 days = 800 man-days. Time = Total work / Number of men = 800 man-days / 10 men = 80 days.

Explanation
Step 1: Calculate 8% of $600 8% of $600 = (8/100) × $600 Step 2: Perform the calculation = 0.08 × $600 = $48

Explanation
Vitamin K is essential for the synthesis of clotting factors in the blood. Its deficiency leads to prolonged bleeding or poor blood clotting.

Explanation
In the modern periodic table, there are 7 periods (horizontal rows) and 18 groups (vertical columns).

Explanation
NO₂ (Nitrogen dioxide) is a covalent compound , made of nonmetals (nitrogen and oxygen) sharing electrons. The others like (NH₄)₂CO₃, HNO₃, and AgCl involve ionic bonding either fully or in part (e.g., NH₄⁺ acts ionically).

Explanation
Dative bond : This is a type of covalent bond where one atom donates both electrons to the bond, forming a coordinate covalent bond. In this case,  NH₃ (ammonia)  (with a lone pair of electrons) acts as the electron donor , and  BF₃ (boron trifluoride)  (electron deficient) acts as the electron acceptor .

Explanation
John Dalton proposed the Atomic Theory in the early 1800s , stating that all elements are made of indivisible atoms. He described atoms as indestructible and identical for each element, laying the foundation of modern chemistry .

Explanation
A reaction in which heat is absorbed is called an endothermic reaction. These reactions lower the temperature of their surrounding area, thereby creating a cooling effect.

Explanation
Given y = 3: Step 1: Calculate y³. y³ = 3³ = 27 Step 2: Calculate y³ - y. y³ - y = 27 - 3 = 24 Step 3: Calculate y³(y³ - y). y³(y³ - y) = 27 × 24 = 648

Explanation
When a projectile moves upward , gravity acts downward. This opposes the vertical motion , so the vertical component of velocity decreases until it becomes zero at the highest point.

Explanation
20 men can construct a building in 40 days. Total work = 20 men × 40 days = 800 man-days. Time = Total work / Number of men = 800 man-days / 10 men = 80 days.