The reagents used in proper sequence are
NaNO2 + H2SO4 / 273K, Cu2I2
NaNO2 + HCl / 278K, Cu/HI
NaNO2 + HCl / 273K, KI
HNO3/273K, Cu2I2
NaNO2 + HCl / 273K – 278K produces HNO2 in situation. It converts 10 aryl amine to Benzene diazonium chloride.