Chrysler Corp. yesterday reported its net profits in the first quarter of the year rose 5 per cent from 1976 to $75.4 million, second best in the company's history.

Sales rose 11 per cent to a record $4 billion.

The nation's No. 3 automaker said its earnings, equal to $1.25 a share, were inflated by a $12.2 million income tax credit equal to 20 cents a share. The results were in line with Wall Street forecasts.

Chrysler earned $72.1 million, or $1.20 a share, in the first quarter of 1976 including a $15 million tax credit. That was the firm's first profit in 18 months.

Worldwide sales for the January-March period rose from $3.6 billion a year ago, while volume climbed 4 per cent to 769,725 units.

However, retail car sales in the United States fell 3 per cent from a year ago to 331,445.

Consolidated Edison Co. of New York York, one of the nation's largest operating utilities, reported an 18.1 per cent gain in first-quarter profits.

Con Ed, which provides electricity, gas and steam service in New York City and some of its suburbs, said it earned $84.2 million in the quarter on revenue of $797.5 million. In the first quarter of 1976, the utility earned $71.6 million on revenue of $733.1 million.

For the 12 months ending March 31, Con Ed's profit totaled $269.7 million, or $4.38 a share, on revenue of $2.9 billion. For the year ended March 31, 1976, earnings were $214.7 million, or $3.49 a share, on revenue of $2.7 billion.