Physical properties are those which can be observed without any change in composition of the substance. Hence, a is the answer.
        
             
        
        
        
The anserr is c that what i think
        
             
        
        
        
The precipitation reaction of sodium nitrate and lead (II) chloride would not happen. No reaction will happen between these substances. Hope this answers the question. Have a nice day.
        
             
        
        
        
The questions tha science can answer are those can be tested to try to find a definite answer.
For example, whether light is wave or particle is matter of science.
Questions that cannot have a definite answer are the field of religion or philosophy, and are out of the boundaries of science.
For example, does a criminal deserve the punishment of not seeing light? It is a moral question, which to be responded needs the intervention of philosophy and that could have different anwers at different times and in different societies.
 
        
             
        
        
        
Hi, the answer is 34.45 , basically 34.