Explanation

The metal that is most active is the one that can displace other metals from their salts. Based on the equations provided:

• Ni can displace Pb from Pb(NO3)2, so Ni is more active than Pb.
• Ni cannot displace Ag from AgNO3 (no reaction), so Ag is less active than Ni.
• Cu cannot displace Ag from AgNO3 (no reaction), so Ag is less active than Cu.

Therefore, the order of reactivity is: Ni > Pb > Cu > Ag

So, Ni is the most active metal among the options.

Explanation

The metal ions of transition metals are paramagnetic. The magnetic moment towards magnetic field is greatest of Fe^+3.

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

NaCl (sodium chloride) is formed by the electrostatic attraction between Na⁺ and Cl⁻ ions.

Such solids are classified as ionic solids due to the presence of ions arranged in a lattice.

Explanation

LiAlH₄ is a strong reducing agent that effectively reduces carboxylic acids to primary alcohols.

NaBH₄ is weaker and typically reduces aldehydes and ketones.

Explanation

The density of water is maximum at 4°C, not 5°C.

At 4°C, water reaches its highest density before expanding when cooled further into ice.

Explanation

Lower temperatures favor the production of ammonia due to the exothermic nature of the reaction, but a moderate temperature (450°C) is typically used for optimal reaction speed and yield.

Explanation

The plasma in the Earth's ionosphere typically has temperatures ranging from about 1000°C to 2000°C

but it can be higher during periods of increased solar activity

Explanation

• Filtration is a process that removes suspended sand particles and insoluble physical impurities from water.
• By passing it through a filter medium, such as sand, gravel, or a membrane.

Explanation

• The gas found in the greatest amount in the universe is Hydrogen.
• Making up 74% of all baryonic matter in the universe.

The elements that make up the universe, ranked in order of their abundance:

• Hydrogen
• Helium
• Oxygen
• Carbon
• Neon
• Iron
• Nitrogen
• Silicon
• Magnesium
• Sulfur