Phase transition temperature of liquid mixtures was studied using the light scattering technique at a laser wavelength of 650 nanometers. The laser beam was focused on the center of a sample cell containing a liquid mixture. Two liquid mixture samples were used as methanol-cyclohexane and methanol-hexane at temperatures varying between 30 and 60 degrees Celsius with resolution of 0.10 degrees Celsius. The intensity of light scattering was measured at an angle of 0 and at 90 degrees. At the

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... cal temperature, the liquid mixtures became opaque, with maximum intensity of light scattering at 90 degrees. Phase transition temperature was studied by two methods. The first separated the liquid mixtures and then increased the temperature to critical opalescence, defined as phase combination temperature. The second method mixed the liquid mixtures well and then decreased the temperature to critical opalescence, defined as the phase separation temperature. The liquid mixture of methanol and cyclohexane at a ratio of methanol 29% gave phase combination temperature of 46.90 degrees Celsius and phase separation temperature of 47.00 degrees Celsius. When changing the ratio of methanol to 26%, 28%, 30% and 32%, both phase combination and phase separation temperatures increased. The liquid mixture of methanol and hexane at a ratio of methanol 22% gave minimum phase combination and phase separation temperatures. When decreasing or increasing the ratio of methanol to 20%, 21%, 23% and 24%, both phase separation and phase combination temperatures increased. Phase combination and phase separation temperatures of the liquid mixtures of methanol-cyclohexane and methanol-hexane were different. The ratio of liquid mixture with the lowest critical temperature is defined as the critical composition.