You're calling title(), xlabel() and ylabel() prior to calling subplot() so instead of applying these functions to the new subpot, you're overwrting the previous one. Move those function to a line that's after subplot(2,4,2).
C29=rand(5,1);
figure(1)
subplot(2,4,2) %<- moved up
title('Case:29','fontsize',10,"fontweight","Bold");
xlabel('Kinetic Mechanisms')
ylabel('SSE')
box on
hold on
for i = 1:length(C29)
h=bar(i,C29(i));
if C29(i) == min(C29)
set(h,'FaceColor','b');
elseif C29(i) == max(C29)
set(h,'FaceColor','r');
else
set(h,'FaceColor','k');
end
end
hold off
This is why it's always good practice to use handles to specify the parent of objects. For example,
s2 = subplot(2,4,2);
title(s2, 'Case:29','fontsize',10,"fontweight","Bold");
xlabel(s2, 'Kinetic Mechanisms')
ylabel(s2, 'SSE')
% ...
h = bar(s2, i,C29(i));
