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in Chemistry
Answer: SF6 has sulfur bonded to 6 fluorine atoms with no lone pairs, requiring sp3d2 hybridization and octahedral geometry.
Answer: Atomic radius increases down a group as new electron shells are added. Rb (Period 5) is the largest among these alkali metals.
Answer: Bromine water (Br2 in water) decolorizes when added to unsaturated compounds (alkenes/alkynes) due to addition across the double/triple bond.
Answer: Na2SO4 dissociates into 2Na+ and SO42-, producing 3 ions per formula unit, so i = 3.
Answer: Molar mass of glucose = 180 g/mol. Mass of 6 C atoms = 72 g. Percent C = (72/180) x 100 = 40%.
Answer: Al2O3 is amphoteric because it reacts with both acids (forming Al3+ salts) and bases (forming aluminate AlO2- ions).
Answer: In O2, the MO configuration gives (bonding electrons - antibonding electrons)/2 = (10-6)/2 = 2.
Answer: From the balanced equation 2H2 + O2 -> 2H2O, 2 moles of H2 produce 2 moles of H2O.
Answer: C4H10 has two structural isomers: n-butane (straight chain) and isobutane (2-methylpropane, branched).
Answer: HF is the weakest hydrohalic acid because the strong H-F bond makes dissociation difficult, despite fluorine\'s high electronegativity.
Answer: Fe has configuration [Ar] 3d6 4s2. When forming Fe2+, two electrons are removed from 4s first, giving [Ar] 3d6.
Answer: NH3 deviates most due to its strong intermolecular hydrogen bonding and larger molecular size compared to the nonpolar gases H2, He, and N2.
Answer: The d-block begins in Period 4 with scandium (Sc, Z=21), which has the first 3d electron: [Ar] 3d1 4s2.
Answer: A buffer consists of a weak acid (CH3COOH) and its conjugate base (CH3COO- from CH3COONa), which resists pH changes.
Answer: In the NaCl (rock salt) structure, each Na+ is surrounded by 6 Cl- ions and each Cl- by 6 Na+ ions, giving a coordination number of 6.
Answer: Aluminum is extracted from molten Al2O3 (dissolved in cryolite) by electrolysis in the Hall-Heroult process due to its high reactivity.
Answer: Acetic acid (CH3COOH) contains the carboxyl group (-COOH), which is a combination of a carbonyl and a hydroxyl group on the same carbon.
Answer: H2SO4 is diprotic (donates 2 H+ ions). Equivalent weight = molar mass / n-factor = 98 / 2 = 49 g/mol.
Answer: sp3d hybridization produces five hybrid orbitals arranged in a trigonal bipyramidal geometry with bond angles of 90 and 120 degrees.
Answer: SO2 has sp2 hybridization with one lone pair on sulfur, giving a bent (angular) molecular geometry with a bond angle of about 119 degrees.