Because of hydrogen bonding, select one: a. lakes freeze from the bottom up b. ice is less dense than liquid water c. ice sinks to the bottom of water d. liquid water is less dense than ice

Carbons 1 and 4 of 1,3−cyclopentadiene are equivalent and give the same carbocation on protonation. likewise, carbons 2 and 3 are equivalent. write the structure of the carbocation formed by protonation of c−2 or c−3 to verify that it is not allylic and therefore not as stable as the one formed by protonation of c−1 or c−4.