Explanation

 CH₃COONH₄ – Salt of weak acid (acetic acid) and weak base (ammonia) → Can be slightly acidic, neutral, or basic depending on their relative strength, but usually basic if acetate dominates

Explanation

 Protons are present in the nucleus of every atom, including hydrogen, which has 1 proton and no neutron in its most common isotope.

Neutrons are present in most nuclei except ordinary hydrogen (¹H).

Electrons are found in the electron cloud, outside the nucleus.

Positrons are antimatter particles, not normally found in atomic nuclei.

Explanation

Explanation

"He heard him sing a song."

Verbs like "hear, see, watch, feel" are followed by the bare infinitive (i.e., the base form of the verb without "to") when used in the active voice.

So, "heard him sing" is correct, not "to sing" or "sang."

Explanation

Explanation

Explanation

Use the Gibbs free energy equation:

$$\Delta G=\Delta H-T\Delta S$$

For a process to be spontaneous, $Delta G < 0$

• If $Delta H < 0$ (exothermic)

• And $Delta S > 0$ (entropy increases)

• Then:

  $$\Delta G=\text{negative}-T\times \text{positive}=\text{always negative}$$

 So, no matter the temperature, $Delta G$ will be negative ⇒ spontaneous at all temperatures

Explanation

The element that is NOT a major bioelement but a trace element in living organisms is D) Zinc (Zn). 

Explanation

At STP, 1 mole of any gas occupies 22.4 dm³.
If 11.2 dm³ = 0.5 mole →
0.5 mole of nitrogen (N₂) = 14 g
→ Full mole = 28 g (molecular mass of N₂)

Explanation

When a convex lens is cut parallel to the principal axis (i.e., horizontally through the center):

• Each half becomes a smaller lens with the same curvature.

• Focal length remains unchanged because the shape (curvature) and refractive index are the same.

• Only the aperture (light-gathering area) is reduced.

So, even after cutting the lens horizontally, the focal length stays the same.