Govt. Exams
Entrance Exams
SiO₂ acts as a flux. It combines with Fe₂O₃ (formed from iron oxidation) to form iron silicate slag (FeSiO₃), which is removed from molten copper.
Reducing power increases with increasing size of halogen (decreasing electronegativity). HI is the strongest reducing agent due to the weak H-I bond.
Transition metals from 3d, 4d, and 5d series can form stable carbonyl complexes. Examples include Fe(CO)₅, Ni(CO)₄, Mo(CO)₆, and W(CO)₆.
Thermal stability of hydrides decreases down the group due to decreasing bond strength (H-O > H-S > H-Se > H-Te). The H-O bond is the strongest.
In this reaction, HCl acts as a reducing agent because Cl⁻ (oxidation state -1) is oxidized to Cl₂ (oxidation state 0). Mn in KMnO₄ is reduced from +7 to +2.
Lattice energy is inversely proportional to the size of ions. As we go from F⁻ to I⁻, ionic size increases, so lattice energy decreases. NaF has the smallest anion, hence highest lattice energy.
Be(OH)₂ is amphoteric and has low solubility. Generally, solubility increases from Mg to Ba, but Be(OH)₂ doesn't follow this trend due to its amphoteric nature.
Ionic character depends on electronegativity difference and charge density. MgO has the highest charge density (smallest cation with 2+ charge) and highest electronegativity difference.
Nitrogen (1s² 2s² 2p³) has a half-filled 2p orbital which provides extra stability. Removing an electron from this configuration requires more energy than from oxygen's configuration.
