Explanation

The reactivity of aldehydes towards nucleophilic addition depends on the size of the alkyl group attached to the carbonyl carbon.

Formaldehyde (HCHO) has no alkyl groups attached to the carbonyl carbon, making it the most reactive

Because there is no steric hindrance, and the electron-donating effect is minimal.

Explanation

 Leading zeros (before the first non-zero digit) are not significant.

In 0.000801, the digits 8, 0, and 1 are significant.

So, it has 3 significant figures

Explanation

Among the listed liquids, heptane (C₇H₁₄) has the greatest molecular weight

Thus the strongest intermolecular forces, lead to the lowest vapor pressure at the same temperature

Explanation

Ammonia (NH₃) has a higher boiling point than phosphine (PH₃)

Ammonia exhibits hydrogen bonding, a stronger intermolecular force than the dipole-dipole forces in phosphine.

Explanation

Be(OH)₂ is an amphoteric hydroxide, meaning it can act as both an acid and a base.

Mg(OH)₂ and Ca(OH)₂ are basic hydroxides.

Explanation

The word dinosaur comes from Greek and means “terrible lizard.”

They were named so because of the similarity between their bones and those of lizards.

The first scientists who discovered their fossils believed they had found the remains of unknown giant reptiles

Explanation

The first gear is the biggest gear in terms of diameter.

It providing higher torque and lower wheel speed.

In contrast, the fifth gear offers the least pulling power but allows the greatest range of speed.

Explanation

The mass can be described as inertia of object which resist its changes in state of motion and rest.

Explanation

 The destruction of wildlife is a multifaceted problem, and the answer is All of these, as deforestation, overfishing, and climate change are all significant drivers of wildlife decline. 

Explanation

 The modern genus of horse, Equus, is believed to have evolved from Dinohippus, via the intermediate form Plesippus.