A list of real estate transactions released last week by D.C. City Council Chairman David A. Clarke is made up largely of single-family homes that have been converted to rental units and not vacant apartment buildings as Clarke claimed, according to a detailed examination of the properties by a real estate organizations.

The difference is significant because Clarke, who is leading the fight to preserve rent control, has used the list at recent public forums to demonstrate that rent controls are not choking off new investment in city rental housing.

Most of the buildings on the list never have been covered by the city's rent control law.

"This list doesn't prove a thing," said Donald Slatton, executive vice president of the Apartment and Office Building Association of Washington. "In his haste to prove his point, he looked at the surface and not at what's really going on."

Clarke did not return several telephone calls. An aide said the chairman was tied up in budget meetings and had not had time to refocus on the issue.

Clarke is sponsoring a bill that will continue current rent controls beyond their April 30 expiration date. Council member John Ray (D-At Large) is sponsoring an opposing measure that would remove rent restrictions as controlled apartments become vacant.

City landlords and developers steadfastly have maintained that rent control is fostering the decline and abandonment of thousands of rental housing units in the District.

The argument is one of the more persuasive in the anti-rent-control arsenal.

But Clarke last week caught opponents by surprise when he produced a list of "29 vacant apartment buildings" that he said had changed hands during last December and January of this year.

At recent hearings and in an interview with a reporter, Clarke said the transactions showed that investors were putting money into vacant apartment buildings for reasons that had nothing to do with rent control.

A detailed examination of the properties by the apartment and office building association found that at least 21 of the 29 buildings were single-family homes that had been converted to apartments of four units or less or were four-family flats.

Four buildings could not be located at the listed addresses, while five transactions involved refinancing or mortgage defaults and not sales, according to the association.

Five apartment buildings, ranging in size from an 11-unit walk-up to a 45-unit building, were among the listed transactions.

Ed Warner, president of a Springfield, Va., plumbing company, said this week he was surprised to learn that one of those transactions involved the 45-unit building his company recently sold.

"We've been struggling with the thing for years and losing our shirts," he said. "We were so anxious to get rid of it we really weren't too concerned who bought it. It was literally a fire sale."

Warner said a range of factors, including rent control, made the building a bad investment.

"We were trying to vacate it as a means of cutting our losses until someone came along and bought it," he said.

The building, located on 23rd Street SE, sold for $229,000 or about $5,500 a unit. In comparison, most apartment buildings sell for $20,000 to $30,000 a unit, according to real estate brokers.

"I don't think these 29 transfers support Mr. Clarke's statements," said Richard Harps, president of the Washington Board of Realtors. "It was unfortunate that in his zeal, he jumped up and waved a list around at all."

Clarke said last week that the list of transactions, which indicated that each of the buildings contained four or more units, was gleaned from weekly reports prepared by Rufus S. Lusk & Son, a Washington-based real estate publishing and information service.

The list was compared with an address directory that denotes abandoned property to determine which buildings were vacant, he said.

"Our report clearly says in it what the use is, and the number of units," said Rufus S. Lusk, III, this week.

In 1983, more than 825 four-family flats were sold in the District compared with 686 sales last year. The decline represents a 17 percent drop in the market, he said.

Last year, sales of apartment buildings with four or more units also declined compared to the previous year, while the sale of converted single-family homes increased by 22 percent, Lusk said.

Real estate brokers said this week that many investors who buy coverted houses are interested in restoring them as single-family homes with a small basement apartment.

Under the current law, buildings with four units or less and buildings that have been vacant since 1980 are exempt from rent controls.

"The bottom line of all this is we're not the ones who said these 29 sales indicated a hot market," said Harps. "What we're suggesting is some very, very poor research was done."