Question

how is testing with benedicts different than testing with iodine?
benedicts solution needs to be heated to work.
benedicts solution starts brown and turns black to indicate glucose.
benedicts solution starts blue and turns orange to indicate starch.
theres no difference between benedicts and lodine, they do the same thing.

Explanation:

Benedict's solution is used to test for reducing sugars (like glucose). It is blue initially and when heated with a reducing sugar, it changes color (green - yellow - orange - red depending on sugar concentration). Iodine is used to test for starch (turns blue - black with starch). So, Benedict's solution needs heating to work (as it's a chemical reaction that is temperature - dependent for the color change to occur in the presence of reducing sugars). The second option is wrong as Benedict's doesn't turn black for glucose. The third option is wrong as Benedict's is for reducing sugars not starch. The fourth option is wrong as they test for different substances (Benedict's - reducing sugars, iodine - starch) and have different procedures (Benedict's needs heating).

Answer:

Benedict’s solution needs to be heated to work.