aieee key correction

hi friends i found that some of the key given by the institutes has some ambiguity the key given by cbse board is the final i found that are maxmimum in chemsitry and physics can u suggest the write answer or corrections to the answer i think they are

    while measuring the speed of sound by performing a resonance column experiment, a student gets its firsy resonance length of 18 cm the he do this same experiment in summer and the answer he get ...................................

     for this i think the answer is 54>X>36

2. this the assertion reason type which is about hte energy released  when heavy nuclei undergo fission.......... can u reply me the answer

3 when it first reacts with concentrated sulphuric acid and then with concetrated nitric acid gives.....reply this answer

4. which of the following factors is of no significance for roastin sulphide ores to carbon reduction directly

5. the electro phile E attacks the benzene ring to generate the intemediate sigma complex. of the folowing lo