At the close of two public meetings of the 74th annual convention of the National Association for the Advancement of Colored People this week, Executive Director Benjamin L. Hooks flamboyantly passed the collection plate among the thousands of delegates and visitors. "Make 'em pay, ushers," he shouted repeatedly. Many within the crowd good-naturedly dropped in bills, checks and coins, but others departed muttering that the practice lacked dignity and taste.

The split reaction to Hooks' collection reflects more fundamental challenges to the man who now has emerged as the unencumbered leader of the nation's oldest and largest civil rights organization.

While passing the hat seemed a minor irritant to northern black professionals, its implications were larger. It brought to mind a leadership style that some dislike and it symbolized some of the deeper problems that the organization faces.

The question now is whether Hooks can reverse the organization's declining membership and gain the money and allegiance of big-city professional blacks who have not supported the organization as much as southern and rural blacks have. For the first time since Hooks succeeded Roy Wilkins in 1977, he is freer to exert his own leadership style. He won the power struggle that has simmered for years with Chairman Margaret Bush Wilson.

Hooks, whose organization consists of 345,000 members in 1,700 chapters, ascends to new prominence at a time when speaker after speaker here has read a litany of political, economic, social and educational challenges to black progress. Virginia Gov. Charles Robb and presidential candidate Reubin Askew are just two of those who decried what Askew called America's "economic apartheid" and Ronald Reagan's turning back the clock on economic and educational opportunities for blacks.

But it remains to be seen whether Hooks can lead the already important organization to address dynamically the more subtle problems of the present.

By any measure, Hooks has an impressive combination of talent. He is a former attorney and judge, ex-commissioner of the Federal Communications Commission and a former Baptist minister in both the North and the South. But he does not come off as pious, staid, old-fashioned or non-progressive.

"I have seen him have people stomping in the aisle and a little later have a sophisticated conversation with a top corporation executive to raise money," said Joseph Madison, the director of the organization's political action committee. Hooks is a dynamic speaker with the power to inspire. During his keynote address Tuesday night, when he challenged Reagan to open a dialogue with black Americans, he had the audience standing, cheering and applauding as if it were a Baptist church.

But Hooks does not possess the personal charisma and style of a Jesse Jackson with his ability to rally the masses. The NAACP is very sensitive about its failure to attract more middle-income blacks. At a news conference, Hooks reiterated that "middle-class blacks need us too."

Hooks will be hampered by several weaknesses, some of them related to the organization's persistent lack of funds. He needs more talented staff to carry out policies such as the "fair share program," the organization's plan to increase black participation in and business with major corporations.

"Ben tends to be scatterbrained because he does so much," says Madison. "He needs a deputy director to carry out administrative responsibility while he generates funds and members and sells our program to the nation. He has to learn to delegate authority. He tries to take too many things on that can be carried out by other people."

The first test of his strength will be whether he can get enough foundation money to register 2 million new voters, the organization's goal. But a more lasting test will be whether he can lead the organization into greater consequence by, among other things, increasing membership and building up the organization's coffers. As one observer put it, "He has no excuses now."