Answer is: Cr⁶⁺.
₂₄Cr 1s²2s²2p⁶3s²3p⁶3d⁵4s¹.
₂₄Cr⁶⁺ 1s²2s²2p⁶3s²3p⁶. 8 valence electrons.
₂₈Ni 1s²2s²2p⁶3s²3p⁶3d⁸4s².
₂₈Ni⁶⁺ 1s²2s²2p⁶3s²3p⁶3d⁴.
₂₆Fe 1s²2s²2p⁶3s²3p⁶3d⁶4s²
₂₆Fe⁶⁺1s²2s²2p⁶3s²3p⁶3d².
₂₇Co 1s²2s²2p⁶3s²3p⁶3d⁷4s²
₂₇Co⁶⁺ 1s²2s²2p⁶3s²3p⁶3d³.
₂₅Mn⁶⁺ 1s²2s²2p⁶3s²3p⁶3d¹.
Answer: Freezing point of a solution will be 
Explanation:
Depression in freezing point is given by:
= Depression in freezing point
i= vant hoff factor = 1 (for non electrolyte)
= freezing point constant = 
m= molality
Weight of solvent (benzene)= 1480 g =1.48 kg
Molar mass of solute (octane) = 114.0 g/mol
Mass of solute (octane) = 220 g
Thus the freezing point of a solution will be
I need help on this one too I think it might be (b)
An acid is a proton donor
Answer:
A) positive; added
Explanation:
Based on the reaction:
2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)
<em>2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.</em>
<em />
That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.
Thus, right answer is:
A) positive; added
