Question

If 10g ice at - 10${}^o$C is added to 40g of water at 15${}^o$C, the temperature of the mixture is

• A. 3.75${}^o$C
• B. 0${}^o$C
• C. 3${}^o$C
• D. -2${}^o$C

Answer 1

The correct option is B 0${}^o$C

$\text{Solution}:$

Heat lost by water to come from ${15}^{o}C$ to $0^{o}C$ is

$H_1=ms\Delta T\frac{40}{1000}\times (4.2\times {10}^3)\times (15-0)=2520J$

Heat required to convert 10g ice into 10 g water at $0^{o}C$ is

$H_2=mL=\frac{10}{100}\times (3.36\times {10}^5)=3360J$

Since $H_2>H_1$, so the whole ice will not be converted into water, whereas the temperature of the whole water will by $0^{o}C$. Therefore the temperature of the mixture is $0^{o}C$

$\text{Hence B is the correct option}$