Explanation

• The electronic configuration 2s¹, 2p⁵ contains six electrons in the second shell.
• This configuration is higher in energy than the ground-state configuration 2s², 2p⁴ of oxygen.
• A species in a higher-energy state may release energy when it changes to a lower-energy, more stable state.

Last verified on 27-10-2026

Explanation

• Hydrochloric acid (HCl) is a strong acid, while barium hydroxide [Ba(OH)₂] is a strong base.
• When HCl is added to Ba(OH)₂, a neutralization reaction occurs: Ba(OH)₂ + 2HCl → BaCl₂ + 2H₂O
• The final concentration of hydrogen ions depends on the relative amounts of acid and base.
• If the added acid is insufficient to neutralize all the base, hydroxide ions remain in excess.
• If enough acid is added to exceed the neutralization point, hydrogen ions become excess.

Last verified on 27-10-2026

Explanation

• Racing cars are made more stable by lowering their centre of gravity, which reduces the tendency to topple while turning.
• A lower centre of gravity helps the car maintain balance when experiencing outward effects during sharp turns.
• Racing cars also use wide tyres and carefully designed suspension systems to improve grip and stability.

Last verified on 27-10-2026

Explanation

Explanation

• A couple consists of two equal and opposite parallel forces acting along different lines of action.
• The resultant force of a couple is zero, but it produces a turning effect called torque or moment of force.
• The torque of a couple is calculated by τ=F×d, where F is the magnitude of either force and d is the perpendicular distance between their lines of action.
• Turning a steering wheel with both hands is a common example of a couple.

Last verified on 26-10-2026