Congress plans to scrutinize Google Inc.’s proposed $3.1 billion acquisition of DoubleClick Inc. to gauge the potential impacts on consumer privacy and competition in the online advertising business.

Hearings at which Google executives will be called to testify are being planned for late summer or early fall by the Senate Judiciary Committee’s antitrust subcommittee and the House Energy and Commerce Committee’s consumer protection subcommittee, according to congressional staffers.