I am baking 1kg chocolate cake and it is already in oven from 50 mins. I'm baking it at 180 degrees temperature. The cake has risen well. But the mixture is not set yet. (I did the toothpick test) I can feel it moving. I have shifted the cake to the first rack a minute before,earlier it was in the middle rack. Please suggest what's wrong?  
Nothing is wrong.   Continue baking until the toothpick comes out clean. The toothpick test is more definitive than time and temperature (and temperatures are not always what they claim, but don't drastically alter yours without feedback from a RELIABLE oven thermometer..)  As I mentioned in a comment on another post, I once had a bad recipe (from a fancy book, even) that I followed with great care, making chocolate soup twice in a row by following the recipe EXACTLY. A wiser than I at the time relative pointed out that there must be a problem with the recipe, and I should just bake until it was done (per toothpick) and it made cake.  A number of factors other than "oven thermostat inaccurate" can lead to times being off - shiny .vs. dark pans, temperature of the batter at the start of cooking, altitude... 